Virginia Department of Forensic Science
Abstracts
Bufotenine: Case Reports and Analysis
Anthony A. Burke, MS, and Annmarie D. Liptak, BA
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic Association of
Forensic Scientists (Harrisburg, PA)
Bufotenine (5-OH Dimethyl Tryptamine), an isomer of Psilocin (4-OH Dimethyl Tryptamine), is an hallucinogen, as well as a topical “aphrodesiac.” It is naturally occurring in certain plants (e.g. Anadenanthera) and toads (e.g. Bufo vulgaris). It is currently a Schedule I controlled substance under both federal and Virginia Code. Bufotenine has recently appeared in the form of a hard, dark-to-light, reddish brown, irregularly shaped, resinous solid material. Because of its closely related chemical structure to Psilocin, Bufotenine presents an interesting problem for structural identification.
This talk presents an overview of pharmacology, case reports and other descriptive literature on Bufotenine, and a description of analytical procedures.
For more information, contact Tony Burke at our Central Laboratory, 804-786-6800.
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Dragon's Blood Incense
Robert R. Steiner, MS
Published in Microgram, 30:258-63 (1997).
A substance described by submitting officers as “raw opium” was submitted to all four of the Division of Forensic Science's laboratories for identification and analysis. The material consisted of a hard, glossy, reddish-brown, amorphous material that breaks easily into a fine powder. Gas chromatographic/mass spectral (GC/MS) analysis of the sample indicated a complex mixture containing numerous compounds of plant origin. Using the Internet, a search on one of the compounds identified as dracorhodin suggested that the material was from Daemonorops draco. A resinous secretion obtained from the ripe fruit of the plant is sold commercially as Dragon's Blood incense. An authentic sample of Dragon's Blood incense was obtained and a GC/MS analysis of the material was identical (except for minor concentration differences) to the material submitted as “raw opium”. None of the compounds identified in the material are controlled or regulated substances. Dragon's Blood is used as an incense and in some occult rituals.
For more information, contact Bob Steiner at our Central Laboratory, 804-786-6800.
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Ketamine: Case Reports
and Analysis
Anthony A. Burke, MS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
KETAMINE (2-(O-Chlorophenyl)-2-(methylamine)cyclohexanone), trade name Ketajet and Ketalar, an analogue of Phencyclidine (PCP), is an anesthetic with hallucinogenic properties which is currently not controlled under the federal code and a Schedule VI controlled substance under Virginia code. It is normally available in injectable form. It has been recently reported in unusual forms and combinations as an abused “street” drug, and is being monitored by the DEA for possible rescheduling, under the federal code.
This talk includes an overview of pharmocology, various case reports, a description of reported and observed mixtures including Ketamine, and a description of the analytical procedures.
For more information, contact Tony Burke at our Central Laboratory, 804-786-6800.
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Methcathinone: Chemistry
and Clandestine Lab Synethesis
Thomas P. Simpson, MS
Paper presented at the 1997 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Roanoke, VA)
An operating clandestine laboratory was seized which was reportedly producing “meth”. Rather than methamphetamine (Schedule II), the product turned out to be methcathinone (Schedule I). Ephedrine (or pseudoephedrine) is the starting material for both methamphetamine (via reduction) and methcathinone (via oxidation). The clandestine synthesis and chemistry of methcathinone will be reviewed.
Information seized from the clandestine laboratory indicated that the Internet may have been utilized as a source of information on methcathinone synthesis. This medium will be examined for its relevance to the forensic chemist.
For more information, contact Tom Simpson at our Western Laboratory, 540-561-6600.
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Rare Anabolic Steroid
Encountered in Northern Virginia
John T. Griffin, BS
Poster presented at the 1995 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Fairfax, VA)
This poster will present general information, packaging and analytical data for Nandrolone Undecanoate, an anabolic steroid which is produced overseas and has only been encountered sparingly in the United States.
For more information, contact John Griffin at our Northern Laboratory, 703-764-4600.
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SWGDRUG
Linda Jackson, MS
SWGDRUG Presentation at Mid-Atlantic Association of Forensic Scientists Meeting 2004
The mission of SWGDRUG is to recommend minimum standards for the forensic examination of seized drugs and to seek their international acceptance. SWGDRUG has previously published recommendations pertaining to Education and Training, Quality Assurance and Analytical Methods. These recommendations were made after seeking input from the forensic community.
SWGDRUG has been working on three new documents. SWGDRUG has two new recommendations, a "Code of Professional Practice" and "Minimum Standards for Method Validation." These can be found on the SWGDRUG website (www.swgdrug.org) and will be published in booklet form when all three documents are finalized as recommendations.
The "Minimum Standards for Sampling" proposal which was available for comment by the forensic community in 2003 has been rewritten and will be available for comment for an additional period. An overview of the Sampling proposal will be presented and contact information will be provided for comments.
For more information, contact Linda Jackson at our Central Laboratory, 804-786-6800.
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Black Powder: History,
Mechanics, and the Forensic Firearm Examination of Muzzle
Loaders
Erich D. Smith, MS, and Julien J. Mason, BS
Paper presented at the 1997 Eastern Regional Conference
for Firearms and Toolmark Examiners (Richmond, VA)
The discovery of black powder is considered by historians as one of the most important mechanical discoveries. Black powder was first used in pyrotechnic devices, war, and incendiary compositions, long before it was harnessed for the production of mechanical work (i.e., muzzle loaders).
With the invention of the self-contained cartridge, many people believed the muzzle loading firearms would fade-out of existence. However, after World War II, muzzle loaders became popular with hunters wanting to make their sport more challenging. States recognizing the popularity extended hunting seasons and increased bag limits for muzzle loading firearms.
Another popular characteristic of muzzle loaders is their legal classification - not a firearm under federal law. The muzzle loading firearm can be sold without background checks and purchased through the mail - state laws vary.
The availability of black powder firearms means they will occasionally wind up in the case work of forensic scientists. The firearms examiner must be properly prepared to: render the firearm safe; evaluate the mechanical operating condition; test-fire for possible comparison; and preserve its condition. In order for the firearms examiner to perform the tasks, in the laboratory, the examiner must have thorough knowledge of muzzle loading firearms and the equipment necessary for proper examinations.
For more information, contact Jay Mason at our Northern Laboratory, 703-764-4600.
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Chemical Evaluation
of Gunshot Residue Resulting from “Lead Free”
Ammunition
Wendy M. Gibson, BS
Paper presented at the 28th Annual Training Seminar (1997)
of the Association of Firearm and Tool Mark Examiners (Annapolis,
MD)
In response to the ever growing environmental concerns over lead, several leading manufacturers have produced "lead free" ammunition.
Gunshot residue patterns were created with both a revolver and a pistol. The patterns were made at a variety of distances, with the firearms in different states of cleanliness, and with several combinations of lead and "lead free" ammunition.
These patterns were evaluated with conventional chemical testing; Sodium Rhodizonate and Greiss. Dithiooxamide (DTO) testing for copper wire was expanded in order to evaluate its usefulness in determining the presence of a pattern.
For more information, contact Wendy Gibson at our Central Laboratory, 804-786-6800.
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Dieseling: Fact or
Fiction?
Scott A. Glass, MA
Paper presented at the 28th Annual Training Seminar (1997)
of the Association of Firearm and Tool Mark Examiners (Annapolis,
MD)
Accidental injuries and deaths attributed to the use of air guns are well documented in forensic science literature. In one such case, the author claimed that a phenomenon known as “dieseling” could significantly increase the muzzle velocity of pellets fired from these weapons. Tests were conducted using a chronograph to measure the muzzle velocities of several types of pellets fired from different types of air guns to test this theory; pellets soaked in diesel fuel, as well as those coated in graphite were also fired and chronographed.
For more information, contact Scott Glass at our Central Laboratory, 804-786-6800.
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Fingernail Ridge Patterns
as a Means of Personal Identification
Ann D. Jones, MS
Paper presented at the 14th Meeting (1996) of the International
Association of Forensic Sciences (Tokyo, Japan)
Although the use of fingernail ridge patterns as a means of personal identification has not necessarily been accepted in the United States under the Frye test (Frye vs. U.S.), it has been upheld under the "general relevancy" test in the Commonwealth of Virginia vs. Joseph Cotton. The results of research demonstrating uniqueness of fingernail striation patterns, persistence over a period of time, and constancy after injury are presented to support such acceptance by the Courts.
For more information, contact Ann Jones at our Central Laboratory, 804-786-6800.
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Improvised Stun Gun
Julien J. Mason, BS
Published in AFTE Journal, 29:1 (Winter 1997) 16-18.
Examination of a fully functional camera revealed alterations indicative of an attempt to manufacture an improvised stun gun.
For more information, contact Jay Mason at our Northern Laboratory, 703-764-4600.
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Muzzle Marks Tell the
Tale
Marcella F. Fierro, MD (Office of the Chief Medical Examiner),
Ann D. Jones, MS, and James L. Pickelman, BS
Paper presented at the 14th Meeting (1996) of the International
Association of Forensic Sciences (Tokyo, Japan)
Contact gunshot wounds often leave muzzle impressions that can be matched to a class of weapon. This information is of special value to death investigators when the wound is through and through and no bullet is available to compare with a suspect weapon; or, when no gun is available for retrospective comparison; or, when there are several weapons available but no bullet to correlate with the weapon or multiple wounds. Methods to compare wounds and muzzles of weapons and a series of photo comparisons of wounds and weapons will be presented.
For more information, contact Ann Jones at our Central Laboratory, 804-786-6800.
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Offensive Versus Defensive
Gunshot Residue Patterns on Hands: Distinguishing Homicide
from Suicide
Marcella F. Fierro, MD (Office of the Chief Medical Examiner),
Ann D. Jones, MS, and James L. Pickelman, BS
Paper presented at the 14th Meeting (1996) of the International
Association of Forensic Sciences (Tokyo, Japan)
Distinguishing offensive from defensive powder residue patterns on hands is important in determining whether close gunshot wounds are homicidal or suicidal. A study of cases where homicide v. suicide was the major issue disclosed that given the weapon in question, similar ammunition, photographs/diagrams of the wounds and the residue patterns on hands, reconstruction of the position of the hands and the muzzle to target distance at the time of firing can be determined. Some reconstructions can rule out a self-inflicted wound. Two test procedures were developed: a test procedure to document patterns of residue deposition by guns, and a procedure, using recyclable models of the hands, for reconstructing and documenting hand position at the time the weapon was fired.
For more information, contact Jim Pickelman at our Central Laboratory, 804-786-6800.
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Shotgun Smoothbore
and Rifled Barrels and the Effects on Pellet Patterns
Paper presented at the 29th Annual Training Seminar (1998)
of the Association of Firearm and Tool Mark Examiners (Tampa,
FL)
Wendy M. Gibson, BS, and Scott A. Glass, MS
Rifled Shotgun Barrel Influences on Pellet
Patterns
AFTE Journal, Volume 29, Number 3, Summer 1997
p. 300-303
A correlation study was undertaken to determine the relationship between pellet patterns from a smooth bore shotgun barrel versus a full rifled shotgun barrel. Using a Remington Wingmaster 870 shotgun, patterns were produced from known distances utilizing various pellet loads in both a smooth and rifled barrel. Shotshells containing lead pellets were used as controls; in addition, patterns were created using steel, bismuth, and tungsten shot, as well as specialty loads, including duplex, triplex and a scatterload. Furthermore, both barrels were shortened to evaluate the effect this would have on pellet patterns.
For more information, contact Wendy Gibson at our Central Laboratory, 804-786-6800.
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Spreader Shotshells
Paper presented at the 1996 Eastern Regional Conference
for Firearms and Toolmark Examiners (Washington, DC)
Wendy M. Gibson, BS
Spreader Loads
Published in AFTE Journal, Volume 32, Number 2,
Spring 2000 p. 166.
With the increase of spreader load manufacturing, a brief overview of some current manufacturing trends is provided. The scattering effect of these loads should be noted when determining distance from pellet patterns when the ammunition may not be known.
For more information, contact Wendy Gibson at our Central Laboratory, 804-786-6800.
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Toolmark References
Wendy M. Gibson, BS
Published in AFTE Journal, 28:4 (October 1996) 266-86.
When performing tool mark exams, the literature may be an important resource, to help facilitate the examiner. The following tool mark index has been compiled in order to make using these literature resources easier. Some articles may be found under multiple headings due to their content. An abstract follows each article that was available for reviewing, and whenever possible the authors abstract was used.
For more information, contact Wendy Gibson at our Central Laboratory, 804-786-6800.
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An Interesting DNA
Data Bank Hit from a Mixture STR Profile
Wendy M. Cohn M. S., George C. Li M.S.
Paper presented at the MAAFS-SAFS Annual Meeting, April
2001, Williamsburg, Virginia
Evidence from an alleged drive-by shooting was submitted by a local police jurisdiction to the Virginia Division of Forensic Science for forensic biology analysis. Eye witness account indicated that 3 males were in the vehicle from which shots were fired, resulting in serious injuries to several people. Through police investigations, three suspects (A, B, and C) were arrested and charged with the crime. The police also recovered a car that they think was the vehicle involved , which turned out to be a rental car.
The laboratory was requested to help establish any link between the suspects and the vehicle. The evidence from the inside the car included a glass bottle, a plastic water bottle and a cigar holder. The blood samples from all three suspect were also submitted for comparison.
DNA STR analysis was conducted on the evidence using the Promega PowerPlex 1.1 typing kit, and useable results were obtained from all the above evidence. The DNA profile from the mouth of the glass bottle was found to be consistent with suspect A. The profile from the mouth of the plastic water bottle turned out to be a mixture of suspect A and B. The DNA profile from the cigar holder was also a mixture profile, but it did not match any of the three suspects.
A search was made with this unknown mixture profile from the cigar holder against the Virginia DNA Data Bank, which contained more than 120,000 STR profiles at the time. The search resulted in 22 moderate stringency hits, all but one of which were eliminated due to the presence of a homozygous locus in the mixture profile. The remaining one matching profile belonged to a female convicted felon. The inmate information on this individual was provided to the police for further investigation, which subsequently revealed that the female turned out to be the mother of suspect C.
For more information, contact Wendy Cohn at our Central Laboratory, 804-786-6800.
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Case Study: Interlaboratory
Comparison Between the FBI Laboratory and the Virginia Division
of Forensic Science on Evidentiary Material Recovered from
Two Jurisdictions (Maryland and Virginia) Utilizing RFLP-DNA
Analysis
Keith H. Howland, PhD (FBI), Karen C. Ambrozy, MFS, and
David A. Pomposini, MS
Paper presented at the 1995 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Fairfax, VA)
In March of 1994, the victim was abducted by a suspect at gun point and forced to commit fellatio as well as forcible vaginal intercourse. The suspect ejaculated in the victim's hair. The suspect also had ejaculated in the vaginal cavity; however, this sample was insufficient for RFLP. The victim could not identify a suspect.
The examiner in the Northern Laboratory had eliminated four suspects through PCR-HLA-DQ alpha typing on semen collected on swabbings from the victim's hair. These swabbings were then sent to the Tidewater DNA section for RFLP analysis along with a known blood sample from the victim. The only lead in the case was a possibility of a suspect who was arrested for a rape/homicide case in Prince George County, Maryland.
A foreign RFLP pattern was obtained from the swabbings from the victim's hair at the genetic loci D1S7, D2S44, D4S139, D10S28, and D17S79. This foreign profile was searched against the Virginia DNA Data Bank with no match.
The results of the sizings of this foreign DNA profile were then compared to the sizing data obtained by the FBI on the suspect arrested in Maryland. The comparisons and subsequent analysis of the suspect's known blood sample will be presented.
For more information, contact Dave Pomposini at our Eastern Laboratory, 757-683-8327.
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Comparative Evaluation of Efficiency and Effectiveness Between Two Hybridization/Detection Methods for Chemiluminescent DNA (RFLP) Analysis
David A. Pomposini, MS, Stephanie Rauscher-Finn, MS, and Jerry W. Sellers, BA
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic Association of Forensic Scientists (Harrisburg, PA)
In October 1995, the Virginia Division of Forensic Science (VA DFS) began implementing a chemiluminescent hybridization/detection protocol for DNA (RFLP) analysis of casework. The procedure employs alkaline phosphatase-conjugated oligonucleotide probes, versus radioisotope-labeled probe inserts. In addition to its distinct safety advantage, the procedure is fairly quick and simple to perform compared to the radioactive technique.
Current protocol practiced by VA DFS includes the "Tupperware" chemiluminescence hybe/detection method in conjunction with commercially-prepared reagents and probes. In an effort to both optimize the quality of RFLP results and maintain or improve cost effectiveness, we have examined an alternative technique for the hybe/detection procedure. We sought to adapt the VA DFS chemiluminescent protocol to include the use of our roller-bottle hybridization oven typically used in the radioactive RFLP analysis method.
The increased efficiency of hybridization for which this equipment was specifically designed suggested that: 1) the hybridization could be optimized due to thorough and even membrane coverage as intended by the equipment's design, and 2) a significant savings could be achieved due to reduced probe/reagent volumes necessary to obtain quality results. The conclusions derived from this comparative study of the efficiency and effectiveness of these two hybe techniques will be discussed.
For more information, contact Dave Pomposini at our Eastern Laboratory, 757-683-8327.
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Dinwiddie Case Study
- A Chronologue of Serological Technology
Lisa C. Schiermeier, MS
Paper presented at the 1995 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Fairfax, VA)
Approximately one year ago, the Virginia Division of Forensic Science (VA DFS) became the first state forensic laboratory in the nation to eschew conventional serological testing (ABO, polymorphic enzyme and serum protein typing) and replace it with DNA PCR-based testing.
Occasionally an old case will find its way back into the laboratory for PCR testing in the hopes of further including the suspect. These cases become chronologues reflecting the technology of the time.
A homicide/sodomy case study will be presented in which the case was originally submitted to the laboratory in March, 1993. Conventional testing (ABO, EsD, and PGM subtyping) was initially conducted.
As our testing capabilities expanded and the case encountered legal hurdles, the evidence was resubmitted for further testing to include HLA DQ-Alpha and Amplitype PM (which includes the LDLR, GYPA, HBGG, D7S8 and GC loci) analysis. There was insufficient DNA to perform RFLP analysis. At the defense's motion, the evidence was forwarded to an independent laboratory for retesting.
This case study will include crime scene photographs, evidence submitted for analysis, results of conventional and PCR testing, and finally the case outcome.
For more information, contact Lisa Schiermeier at our Central Laboratory, 804-786-6800.
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Evaluation of the Reliability
of the GenePrint™ STR Multiplex System CSF1PO-TPOX-THO1
(Promega) During Routine Forensic Casework Analysis
Brian L. Covington, MS, Bradford C. Jenkins, MS, Barbara
E. Llewellyn, MS, and Jeffrey D. Ban, BS
Poster presented at the 49th Annual Meeting (1997) of the
American Academy of Forensic Sciences (New York, NY)
Objective: To evaluate the performance of the GenePrint™ STR Multiplex System CSF1PO-TPOX-THO1 (Promega) under normal forensic casework conditions.
There are many advantages offered by the polymerase chain reaction (PCR), such as the ability to analyze partially degraded samples, greater sensitivity, and the ability to analyze more samples in less time. These advantages have led to research into new techniques for utilizing the PCR in the area of forensic casework analysis. Short tandem repeat (STR) loci are highly informative, polymorphic loci that consist of 3 to 7 base pairs (bp) in length. The small size of the STR's facilitates their simultaneous amplification in a multiplex PCR, in which two or more loci are amplified in one reaction from a single DNA sample.
This study was devised to evaluate the performance of the GenePrint™ STR Multiplex System CSF1PO-TPOX-THO1 from Promega using non-probative case samples in order to determine the reliability of this system under routine forensic casework conditions. The major focus of this study was to determine the effectiveness of this system in distinguishing between mixed body fluid stains, and the consistency with which interpretable results are obtained. Twenty cases, which included all known blood samples as well as evidence stains, were analyzed. The blood samples and sperm and non-sperm fractions of the mixed body fluid stains were amplified using the triplex CSF1PO-TPOX-THO1 followed by evaluation utilizing denaturing polyacrylamide gel electrophoresis with subsequent silver staining.
This study has demonstrated that typing of the STR complex CSF1PO-TPOX-THO1 by the PCR using the GenePrint™ STR Multiplex System (Promega) can be accomplished with confidence, allowing reliable, interpretable results to be obtained on a variety of different samples commonly encountered during routine forensic analysis.
For more information, contact Brian Covington at our Central Laboratory, 804-786-6800.
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Observations Associated
with CODIS Hits Obtained by Searching a Large DNA Databank
George C. Li, M.S. Linda Johnston, B.S.
Paper presented at the 11th International Symposium on Human
Identification, October 2000, Biloxi, Mississippi
In Virginia, the use of the RFLP technique in the analysis
of convicted offender samples was discontinued in mid-1997,
in favor of the STR fluorescence technique. Before the end
of 1998, the STR fluorescence technique also replaced RFLP
for the analysis of evidence samples from criminal cases.
Since the fall of 1998, hits have occurred on an increasingly regular basis as the size of the convicted offender databank increased. Currently, at least ten hits occur in an average month. Hits are being made between an unsolved case vs. other unsolved case(s), an unsolved case vs. a solved case, and an unsolved case vs. a convicted offender. Virginia's CODIS convicted offender databank currently contains more than 110,000 STR profiles, with the majority of the profiles containing data at eight of the 13 core CODIS STR loci. Unsolved cases are being analyzed using STR technology statewide at the rate of approximately 10 to 20 per month.
As a result of the large number of hits, observations and correlations have been made on factors such as the particular types of cases being solved by CODIS hits, the prior offenses of the convicted offender, the percentage of cases solved on the initial search, and the number of hits made using STR data vs. RFLP data. One observation is that a significant number of the convicted offenders who were Ahit@ by unsolved rape cases were previously convicted of only nonviolent crimes. It has also been noted that a large number of cases are solved on the initial search, probably as a result of the databank size. In addition, a substantial percentage of old unsolved cases resubmitted for STR analysis and a CODIS search result in hits.
For more information, contact George Li at our Central Laboratory, 804-786-6800.
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Population Studies
of the STR System CSF1PO, TPOX, and THO1
Barbara E. Llewellyn, MS, Virginia L. Fristoe, MS, and
Jeffrey D. Ban, BS
Paper presented at the 48th Annual Meeting (1996) of the
American Academy of Forensic Sciences (Nashville, TN)
Although DNA analysis using RFLP and Southern blotting techniques is a very discriminating technique, the large product size can make it less suitable for use with degraded DNA. The polymerase chain reaction (PCR) analysis offers many advantages over RFLP and Southern blotting techniques, such as lower costs, greater sensitivity, better toleration of degradation, and less time required to perform the analyses. Due to the many advantages of PCR, new methods of analysis are being investigated for use in forensic science. Short tandem repeat (STR) loci are highly informative polymorphic loci that consist of short, repetitive sequences of 3 to 7 base pairs (bp) in length. These repetitive sequences are polymorphic due to variation in the base pair length among individuals, therefore allowing for discrimation between individuals. The repeats can be amplified using the PCR, enabling precise allele designation based on the length of the repeat unit. Since STR typing requires only a small amount of DNA and since the amplification products are less than 400 bp long, the system can be used with DNA that may be degraded. The small size of the STRs facilitates their simultaneous amplification in a multiplex PCR, in which two or more loci are amplified in one reaction from a single DNA sample. The largest advantage to multiplex PCR analysis is that it allows for a more efficient analysis with less time and costs. The Virginia Division of Forensic Science has contructed population data bases for Caucasian, African American, and Hispanic populations using the GenePrint™ STR system (Promega). DNA samples from unrelated individuals were amplified using the triplex CSF1PO, TPOX, and THO1. The PCR products were resolved on a denaturing polyacrylamide gel electophoresis system with subsequent silver staining. Population data was generated for each STR locus and allele frequencies calculated for each population. At least 9 alleles have been identified for CSF1PO, 8 alleles for TPOX, and 7 alleles for THO1. The total discrimination power of this STR triplex ranges from .856 to .920 depending on the population.
For more information, contact Jeff Ban at our Central Laboratory, 804-786-6800.
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Population Studies
of the STR System CSF1PO, TPOX, and THO1
Barbara E. Llewellyn, MS, Virginia L. Fristoe, MS, Brian
T. Shannon, MS, and Jeffrey D. Ban, BS
Poster presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
[same abstract as above paper]
For more information, contact Brian Shannon at our Central Laboratory, 804-786-6800.
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Precision Study of
STR Analysis of the FFFL Loci using the FMBIO-100 Fluorescent
Imaging System
Michelle Upshaw, BS (Virginia Commonwealth University),
Barbara E. Llewellyn, MS, and Jeffrey D. Ban, BS
Paper presented at the 1997 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Roanoke, VA)
The Hitachi FMBIO-100 Fluorescent Imaging System is a high volume analysis instrument designed to scan electrophoretic gels using a solid state green laser. The laser detects differing wavelengths of light which are emitted from fluorescently tagged DNA in the gel. The fluorescent signal that is emitted is analyzed using a Macintosh computer with specialized software, which enables the analyst to size the bands and thus determine a DNA profile for the sample.
Short tandem repeat (STR) analysis using the polymerase chain reaction (PCR) with fluorescent detection systems is gaining in popularity, in part due to the safety, sensitivity, speed, and accuracy associated with these methods. It is important to validate the precision of the instrument before it is used for casework analyses. Therefore, an experiment was designed to test the precision of the FMBIO-100 Fluorescent Imaging System.
Five (5) known blood samples were extracted, purified, and amplified using the GenePrint™ FFFL Fluorescent STR System Kit (Promega). Each amplified product was electrophoresed on a Gel-Mix 6 (Gibco/BRL) acrylamide gel using a SA32 electrophoresis unit (Gibco/BRL). Twenty (20) individual amplifications and gels were run. The gels were scanned on the FMBIO-100 and analyzed on the Macintosh computer using the FMBIO analysis software. The results of the precision study will be presented here.
For more information, contact Jeff Ban at our Central Laboratory, 804-786-6800.
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Primate Specific Results
with Quantiblot™ Method for DNA Quantitation
R. Elizabeth Bush, MFS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
The Quantiblot™ test kit is used routinely for DNA quantitation prior to PCR analysis. One of the advantages of this method of quantitation is that human species can also be confirmed. Human species is confirmed because the test incorporates the use of a probe that is complementary to a primate-specific alpha satellite DNA sequence at the locus D17Z1. The manufacturer of the Quantiblot™ kit reports that non-primate blood can react with this test but at a very low level (<.15 ng). Non-primate blood samples, of the same and different species tested by the manufacturer, were tested to verify the species specificity of this test. Chelex extractions of none-primate blood samples were subjected to slot blot analysis using the Quantiblot™ kit and chemiluminesent detection. The Chelex extract of one (1) species yielded a high level of DNA with this method. Organic extractions of this same sample resulted in no detectable DNA. The results of this study will be presented along with suggestions on achieving primate specific results with the Quantiblot™ Kit.
For more information, contact Elizabeth Bush at our Western Laboratory, 540-561-6600.
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Revisiting Unsolved
Cases: Studies Involving PCR Analysis of Old Cases
Lisa C. Schiermeier, MS
Paper presented at the 50th Anniversary Meeting (1998) of
the American Academy of Forensic Sciences (San Francisco,
CA)
The objective of this paper is to increase understanding and appreciation of the value of DNA PCR analysis as applied to critical evidence in old, unsolved cases.
Since the introduction of polymerase chain reaction (PCR) analysis into the forensic arena, scientists have obtained results from samples which conventional serological analyses would have never produced. The PCR method involves the amplification of discrete areas of the DNA strand. Thus, this method lends itself to the analysis of limited amounts of genetic material as well as to old stains. Conventional serological analyses include ABO typing, enzyme typing such as the Esterase D (EsD), Phosphoglucomutase (PGM) and Peptidase A (Pep A) systems, and Haptoglobin (Hp) protein typing. While these methods require well-preserved and large amounts of sample, they lack discrimination and are limited in sample variety. Restriction fragment length polymorphism (RFLP) analysis is an additional method available for profiling biological stains. Results can be very discriminating. However, large, undegraded samples are necessary in order to obtain results.
Particularly since the implementation of DNA PCR-based typing in 1994, the Virginia Division of Forensic Science Forensic Biology Section (VA-DFS) has seen an increase in requests to re-analyze old, unsolved cases. The Division accepts old cases on a case-by-case basis, pending approval by the Forensic Biology Program Manager. These cases involve samples which were previously analyzed using conventional methods or a combination of conventional methods with DNA RFLP analysis, as well as samples which were not conducive to these methods. Where conventional typing results were obtained, they generally lacked discrimination. In all instances, no meaningful RFLP results were obtained (no foreign profile was detected or an insufficient amount of high molecular weight DNA was recovered).
Three case studies will be presented, demonstrating the usefulness of PCR analysis in clearing unsolved cases. The first case involves the 1985 murder and attempted murder of two young women. Conventional serology yielded no foreign ABO or PGM types in the seminal fluid stains found on the victims. RFLP analysis yielded insufficient high molecular weight DNA. The second case involves a 1981 homicide in which conventional serological analyses of crime scene stains matched the victim. Additional evidence, previously unsuitable for conventional analyses, was submitted for PCR analysis. The third case involves the 1982 rape and murder of a young woman. No foreign ABO or PGM types were obtained and subsequent RFLP analysis yielded no foreign profile. Each of these cases was recently resubmitted to VA-DFS for PCR analysis. AmpliType® PM + DQA1, CTT and D1S80 systems were utilized on the most probative evidence in each case.
Details of the cases will be presented along with the results of the PCR analyses. The results proved to be of value to the investigating agencies since detectives were able to clear these unsolved cases. In the 1982 rape and murder case, the suspect admitted to the murder when he was confronted with the results of the PCR analysis. Detectives involved in the 1985 murder and attempted murder cases were not able to obtain a blood sample from the suspect. However, the blood sample collected by the medical examiner for toxicology screens was then forwarded for DNA analysis and was found to be consistent with the evidence. The evidence in the 1981 homicide case was able to place the suspect in the victim's vehicle, which was in contrast to the suspect's previous statements. The prosecution has not yet confirmed whether they will pursue a trial. Specific details regarding the aforementioned cases will be discussed as well as the complications encountered in re-examining and adjudicating old cases.
For more information, contact Lisa Schiermeier at our Central Laboratory, 804-786-6800.
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Sexual Assault Nurse
Examiners - A New Approach to Evidence Collection
Lisa C. Schiermeier, MS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
The scenarios are all too similar: A victim is raped, sometimes beaten, and threatened not to tell anyone. A child confides in a teacher that the mother's boyfriend has been touching him/her in an inappropriate way. An estranged husband breaks into his wife's house and sodomizes her. For sexual assault victims, the experiences have been degrading and humiliating, and will haunt them the rest of their lives. These victims, along with the associated forensic evidence, are often the only witnesses the criminal justice system may look to for apprehension and prosecution of such offenders. However, without a proper medical examination, such evidence and documentation can be lost.
The Sexual Assault Nurse Examiner (SANE) is a nurse who not only has specialized training in the collection and preservation of evidence, but who has also been trained to record victim's statements and to recognize physical injuries which may be consistent with a sexual assault.
The Virginia Division of Forensic Science (VA DFS) trains hundreds of police officers/investigators in the proper documentation and collection of physical evidence from crime scenes. The only difference between them and nurses is that the nurses' crime scene is a human body. Recognizing the impact that evidence collection methods have on the outcome of sexual assault cases, VA DFS joined a local hospital in co-sponsoring a SANE Certification. Although the core curriculum was designed based on that of other SANE classes, some unique topics were also added.
The forensic purposes behind the SANE program were to train emergency room nurses in the effective and appropriate collection of evidence from sexual assault victims using the VA DFS Physical Evidence Recovery Kits, to include packaging and chain-of-custody issues to equip them with the knowledge to adequately address "non-routine" cases. The SANE program also seeks to familiarize nurses in case preparation and presentation, courtroom procedure and effective testimony, and to teach nurses the legal implications associated with physical findings and evidence collection and to train them in proper documentation, including photography, of these findings.
The forensic benefits of the SANE certification include: more thorough and consistent evidence collection, enhanced communication with the laboratory and investigation officers, and an increased confidence on the nurse's part to collect something they might not have otherwise recognized as potentially valuable evidence. Investigators and prosecutors have seen these and other benefits (such as victim's communication with the nurse about specifics of the alleged assault), thus enabling the nurse to collect the appropriate evidence during the examination; nurses understanding and following chain-of-custody rules; and improved expert testimony by SANE concerning medical hallmarks of rape.
For more information, contact Lisa Schiermeier at our Central Laboratory, 804-786-6800.
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Sexual Assault Nurse
Examiners - An Essential Link Between the Sexual Assault
Victim and the Forensic Laboratory
Lisa C. Schiermeier, MS
Paper presented at the 48th Annual Meeting (1996) of the
American Academy of Forensic Sciences (Nashville, TN)
The concept of a Sexual Assault Nurse Examiner (SANE) is becoming more common throughout the United States. These nurses are specially trained in the care of sexual assault victims which begins when the victim arrives at the medical facility. The SANE completes the initial interview and statement, conducts (or assists with) the physical and gynecological examinations, collects physical evidence, and counsels the victim before discharge. If the case goes to court, the SANE may testify as an expert witness to the physical findings and evidence chain of custody. Thus, these nurses play a critical role in the adjudication of sexual assault cases.
Recognizing the importance of this role and the impact that evidence collection methods have on the outcome of sexual assault cases, Virginia Division of Forensic Science (VA DFS) joined a local hospital in co-sponsoring a SANE Certification in which the curriculum was designed to meet the needs of the victim, the law enforcement community, the forensic science community, and the legal community. In order to become certified, participants must successfully complete a forty hour training seminar and a forty hour clinical rotation.
The seminar curriculum includes such topics as the collection of Physical Evidence, Police Rules and Responsibilities, the Role of Victim Witness and Child Protective Services, Proper Documentation, the Human Sexual Response, Forensic Photography, Rape Trauma Syndrome, Child Sexual Abuse, Forensic DNA Analysis, Profiling Rapists, and Patterned Injuries. In addition, some unique topics include "hands-on" photography with follow-up photograph critiques, Moot court Testimony held in a local courtroom, and written and practical examinations at the end of the seminar. After successful completion of the seminar, the nurses are considered SANE Candidates.
In order to achieve full certification, the Candidates must also complete clinical rotations. The goal of the rotations is to acquaint the SANE with the community resources available to victims of sexual assault. There are a predetermined number of hours the Candidate is required to spend with sexual assault investigators, prosecuting attorneys, victim witness coordinators, forensic scientists, and medical staff conducting gynecological examinations. Once all the requirements are completed, the Candidate is awarded the Sexual Assault Nurse Examiner Certificate.
As a result of co-sponsoring this Certification, not only has the VA DFS experienced improved collection and preservation of forensic evidence, more thorough documentation, and a willingness to collect evidence in non-routine situation, but it has also played a role in determining the curriculum and teaching appropriate topics for the Seminar. In addition, the communication between the forensic scientists and the Sexual Assault Nurse Examiners has improved dramatically.
For more information, contact Lisa Schiermeier at our Central Laboratory, 804-786-6800.
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STRs: Comparison of
Silver-Staining and Fluorescent DNA Analysis Using the CTT
and CTTv Loci
Michelle T. Squyars, BS (Virginia Commonwealth University),
Tara L. Savage, BS (Virginia Commonwealth University), Virginia
L. Fristoe, MS, Barbara E. Llewellyn, MS, and Jeffrey D.
Ban, BS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
Fluorescent imaging systems have become an important tool to short tandem repeat (STR) analysis in forensic casework and data banking. Due to various limiting factors such as cost and other resource considerations many labs will continue to analyze multiplex STR systems using silver-staining detection instead of a flourescence-base system. The purpose of this study is to evaluate the reliability of fluorescently labeled DNA in comparison to silver-stained DNA profiles of amplofied STR loci. Twelve samples were amplified using the CTT GenePrint™ Amplification Kit, and the CTTv GenePrint™ Fluorescent STR Systems PCR Amplification Kit (Promega). The CTT kit contains several genetic loci, including: CSF1PO, TPOX, and THO1. The CTTv kit contains the same loci, with the addition of vWA. Following amplification, the samples were typed by separation on denaturing polyacrylamide gels followed by silver staining for the CTT amplified samples, and fluorescent imaging using the FMBIO (Hitachi) fluorescent imaging system for the CTTv amplified samples. Comparison of results will be presented.
For more information, contact Jeff Ban at our Central Laboratory, 804-786-6800.
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STRs: Precision Study
of the Hitachi FMBIO Using CTTv Loci
Tara L. Savage, BS (Virginia Commonwealth University),
Michelle T. Squyars, BS (Virginia Commonwealth University),
Barbara E. Llewellyn, MS, Virginia L. Fristoe, MS, and Jeffrey
D. Ban, BS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
Short tandem repeat (STR) polymorphisms consist of repeated DNA sequences of 3 to 7 base pairs in length. The analysis of these highly informative polymorphic loci by automated fluorescence is rapidly gaining popularity in the realm of forensic science. One type of fluorescence-based system is the Hitachi FMBIO-100: Fluorescent Method Image Analyzer. The FMBIO detects fluorescent signals on polyacrylamide gels as well as other media. The system is used in conjunction with an Apple Macintosh computer, the appropriate software for data analysis, and fluorescent dyes for sample labeling. The purpose of this study is to evaluate the precision and reproducibility of the FMBIO-100 using amplified CTTv loci. Extracted DNA from five different individuals was repeatedly amplified using the CTTv Fluorescent STR Systems PCR Amplification Kit (Promega). The kit contains fluorescently labelled primers for the genetic loci CFSF1PO, TPOX, THO1, and vWA. Following amplifications, these samples were typed by separation on denaturing polyacrylamide gels followed by automated fluorescent analysis with the Hitachi FMBIO-100. An inter gel and intra gel comparison study was conducted. The results of this precision study will be presented.
For more information, contact Jeff Ban at our Central Laboratory, 804-786-6800.
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STR Validation Studies
of Mixed Stains
Amanda Blanchard, BS (Virginia Commonwealth University),
Barbara E. Llewellyn, MS, and Jeffrey D. Ban, BS
Paper presented at the 1997 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Roanoke, VA)
Short Tandem Repeat (STR) validation studies have become an integral part of forensic research in the implementation of new DNA systems on forensic casework samples. Mixed stains propose unique obstacles within sample preparation and typing analysis. To address this, emphasis has been placed on the ability to distinguish typing of sperm cells from epithelial cells. The occurance of stutter bands, artifacts, preferential amplification and allelic drop out can also create complications in genetic typing. Therefore, it is imperative that interpretation guidelines be established.
In this study, mixed stains from five samples were extracted, amplified and typed using the GenePrint™ FFFL Fluorescent STR Typing Kit (Promega). A variety of dilutions were analyzed in order to determine the concentration at which a weak minor component would have the same intensity as a stutter band. The gels were visualized using an FMBIO-100 Fluorescent Imaging System. Peak areas and heights were calculated for all alleles at each locus in order to determine an empirical value used to differentiate between a real band and a stutter band. This study, in addition to the studies being conducted in conjunction with the FBI STR Standardization Project, will enable the analyst to establish criteria for determining when a weak allele will be classified as a stutter band versus a weak interpretable allele.
For more information, contact Jeff Ban at our Central Laboratory, 804-786-6800.
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Validation of the
Co-Amplification of the Amelogenin Gene with HLA DQ-Alpha
Barbara E. Llewellyn, MS, Susan Burley, BS (Virginia
Commonwealth University), and Jeffrey D. Ban, BS
Paper presented at the 1995 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Fairfax, VA)
A gender determination test would be useful in cases involving unidentified remains as well as in cases where a homicide is suspected and blood is found, but a body is never recovered. Amelogenin is the major extracellular protein in the developing tooth bud and can be used for gender determination. Although the amelogenin gene is found on both the X and Y chromosomes, the segment defined on the X chromosome is 106 base pairs (bp) and on the Y chromosome is 112 bp. Therefore, if only one PCR product is seen at 106 bp it is of female (X,X) origin, while a sample with both 106 bp and 112 bp bands is of male (X,Y) origin.
Taylor, et al. (1994) designed a procedure which allows for the co-amplification of HLA DQ-Alpha and the amelogenin gene utilizing the amplitype mix and amplification protocol. The Virginia Division of Forensic Science is undertaking validation studies on this procedure. Typing results on twenty known female and twenty known male blood samples as well as samples from individuals who are XXY, XXX, and XYY will be discussed.
For more information, contact Jeff Ban at our Central Laboratory, 804-786-6800.
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Virginia's Approach
to STR Mixture Interpretation and CODIS Entry
George C. Li, MS
Paper presented at the 2001 MAAFS-SAFS Meeting DNA Workshop
on 4/24/2001.
In recent years, STR-Fluorescent multiplex kits are increasingly being used by forensic laboratories in the analysis of convicted offender samples, as well as forensic case samples.
The fluorescent STR technology itself is
very amenable to the analysis of convicted offender samples
because it is easily automated and adapted for high throughput.
However, the sensitivity of the fluorescent STR technology,
and the fact that individual STR loci are only moderately
polymorphic when each locus is considered by itself, can
cause difficulties in interpretation when mixture profiles
are detected in forensic samples. Known artifacts such as
stutter peaks or bands can also add to the difficulty in
mixture profile interpretation.
The Combined DNA Index System (CODIS) is becoming more effective in solving non-subject cases as more forensic laboratories compile large DNA databases of convicted offenders. A search of non-mixture forensic case profiles against the offender databases usually poses no problem. However, a search of a STR mixture profile against the database may result in a large number of possible candidates, many of which cannot be eliminated as possible contributors. A search of only a portion of the mixture profile can be problematic; therefore great care must be taken in choosing the "correct" alleles in each locus for search purposes.
These issues are being addressed by the Virginia Division of Forensic Science in the form of mixture interpretation and CODIS data entry guidelines. This session consists of a discussion of these issues together with examples of some actual case mixture profile interpretations.
For more information, contact George Li at our Central Laboratory, 804-786-6800.
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Virginia's Experience
with the combined DNA Index System (CODIS)
George C. Li, MS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
The combined DNA Index Systems (CODIS) was developed by the FBI as a computer system for the indexing of DNA results at the local, state, and national levels. CODIS was designed to facilitate comparisons of DNA records, in order to generate investigative leads for law enforcement.
In 1991, the Virginia Division of Forensic Science became one of the first CODIS pilot laboratories. At that time the Division did not yet conduct unsub casework, and the CODIS system was used primarily as a platform for sizing DNA (RFLP) autorads from subject cases in the Central Laboratory in Richmond, and for beta testing purposes.
Currently the CODIS system in Virginia consists of a networked computer system in the Central Laboratory, where DNA (RFLP) profiles from subject cases, unsub cases, and convicted felons are indexed and searched using the CODIS system. The Tidewater Laboratory in Norfolk utilizes the CODIS system as well, and is linked to the Central Laboratory via a secure modem.
Searches of unsub cases against the convicted felon data bank using the CODIS system have yielded 5 "hits" to date.
In this presentation some of our experiences as a CODIS pilot laboratory will be discussed. Several unsub case "hits" using CODIS will also be presented.
For more information, contact George Li at our Central Laboratory, 804-786-6800.
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Brother Electronic
Label Machine: Label Production, Ribbon Legibility and Identification
Gordon C. Menzies, Jr., BA
Paper presented at the 1997 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Roanoke, VA)
A description of the process used by the Brother Electronic Label Machine to produce labels, a description of reading the ribbon, and a method of identifying the product from a specific ribbon.
For more information, contact Gordon Menzies at our Western Laboratory, 540-561-6600.
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Forgery of an Entire
Document Using Simulation
Thomas E. W. Goyne, MFS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
This paper discusses the forgery of a handwritten insurance statement by attempting to simulate the handwriting style of a juvenile and a domestic court judge. The suspect, using a handwritten insurance statement previously issued by the judge in a child support case, was able to produce a new insurance statement which made greater financial requirements on the other party. While the document had a striking resemblance to the judge's handwriting style, it contained many features consistent with simulation.
For more information, contact Mike Moore at our Central Laboratory, 804-786-6800.
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Identifiability of
the Flatbed Scanner and its Products (Graphics Files and
Printed Results)
Richard A. Horton, MEd
Paper presented at the 1998 Annual Meeting of the Southeastern
Association of Forensic Document Examiners (Conyers, GA)
and at the 56th Annual Conference (1998) of the American
Society of Questioned Document Examiners (Indianapolis,
IN)
This study addresses the ability to identify the specific original document, scanner or graphics file from which a scanned product (graphics file or printed result) was made. Contaminants in many types of paper are often reproduced by the scanner, allowing a correlation of the product to an original document. Further, Small Computer Systems Interface (SCSI) chain noise (environmental interference) frequently produces a non-repeating series of marks allowing a graphics file to be correlated to a printed result. Photocopier-type defects from the scanner platen and internal components may also allow the correlation of a specific scanner to the printed result.
For more information, contact Rick Horton at our Western Laboratory, 540-561-6600.
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Case Study: A Robbery
and a Homicide in Arlington County, Virginia
MPO Edward Robinson, MFS (Arlington County Police Department),
Robert B. Hallet, BS, and Eileen A. Davis, MFS
Paper presented at the 1996 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Harrisburg, PA)
In January of 1992, the 68-year-old female victim was bound and gagged using materials available in her residence. A number of items were stolen including her VCR, ATM card/PIN #, cash and jewelry. Ladder marks and shoeprints were noted outside her residence and a ladder was found nearby.
At a separate location, the male homicide victim was located. In an unrelated traffic stop, the suspect was detained and incriminating evidence was seized. As the investigation of these two cases unfolded, it became clear that they were interrelated. The evidence included shoeprint impressions, blood, hairs and a secondary fiber transfer from the robbery victim's residence to the homicide victim.
This case study will include crime scene photographs and discussion, results of the analyses of submitted evidence and the outcome of the jury trial.
For more information, contact Eileen Davis at our Central Laboratory, 804-786-6800.
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Considerations for
a Lab Moving into the Field of Gunshot Residue by Automated
SEM/EDX
Douglas H. DeGaetano, MS
Paper presented at the 1997 Annual Meeting of the Mid-Atlantic
Association of Forensic Scientists (Roanoke, VA)
The number of Forensic Laboratories using automated Scanning Electron Microscopy and Energy Dispersive X-Ray (SEM/EDX) for the analysis of gunshot residue has increased over the past ten years. This is, no doubt, due in part to an increase in the number of manufacturers offering this equipment and the introduction of a more affordable instrument by the R. J. Lee Group, Inc. The author has been involved in the setup and operation of two different automated SEM/EDX systems; one in the private sector and one with the Virginia Division of Forensic Science. A number of practical considerations will be addressed with regard to a laboratory moving into this area of analysis. Topics to be discussed include: the probative value of the analysis, caseload requirements, sample volume and speed capabilities for various instruments, compatibility of SEM and EDX systems, manufacturers' demos, sample collection and analysis techniques.
For more information, contact Doug DeGaetano at our Central Laboratory, 804-786-6800.
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SEM/EDX Identification
of Gunshot Residue Particles in Histologic Sections from
Wound Tracks
Jack Daniel, MD (Office of
the Chief Medical Examiner), Vicki Barber (Office of the
Chief Medical Examiner), Douglas H. DeGaetano, MS, and Ann
D. Jones, MS
Paper presented at the 50th Anniversary Meeting (1998) of
the American Academy of Forensic Sciences (San Francisco,
CA)
We report a method for locating and identifying gunshot residue particles in histologic sections of gunshot wound tracks.
In the investigation of cases of injury by gunfire, various methods of testing for gunshot residue (GSR) on the hands of individuals have been developed. Our laboratory utilizes an automated Scanning Electron Microscope and Energy Dispersive X-Ray [SEM/EDX] analysis system for this purpose. Using this method, individual particles of specific primer residue material ranging in diameter from 1 to 100 microns can be visualized, identified and counted.
As an aid to addressing range-of-fire questions, it is common practice to excise a suspected entrance gunshot wound track (GSW) and to prepare histologic sections for light microscopic examination from this material. Depending upon range of fire (among other variables), entrance wounds may display varying quantities of black soot material along the wound track. Such black, sooty deposits are typically composed of particles in the range of 10 to 100 microns in diameter.
It was hypothesized that:
-
the black, sooty material seen in histologic sections of entrance GSWs contains primer residues (i.e., particles containing lead, barium and antimony);
-
the automated SEM/EDX system could be used to localize and identify GSR materials on conventional slide-mounted histologic sections; and
- a useful visual display correlating conventional histologic findings with primer residue distribution could be produced.
Unstained slides without coverslips (as well as H&E stained slides from which coverslips had been removed) were carbon-coated using a Denton vacuum evaporator and were examined using an automated SEM/EDX system consisting of a Zeiss DSM 940A and Oxford eXL1 with a Tetra backscatter detector. Using a modified automated GSR identification software program, individual colors were assigned to particles containing specific combinations of elements, resulting in a color GSR map showing the location and identification of bullet lead and primer residue particles in tissue sections. Such maps were compared with corresponding H&E sections to facilitate identification of questioned materials.
Color GSR maps showed large amounts of primer residue present in contact and some close range GSWs, with generally only bullet lead with minimal primer residue in distant GSWs. The maps showed that bullet lead and primer residue particles were co-mingled with the nonspecific black soot material described above. Using only the light microscope, neither bullet lead nor primer residue particles could be distinguished morphologically from the surrounding soot material.
We conclude that the automated SEM/EDX system can readily identify, localize and illustrate the distribution of specific primer residue materials present in histologic preparations of GSW tracks. Further study is warranted to determine:
- the efficacy of this method using fresh and archival
clinical GSW material; and
- whether quantitative information useful in addressing practical range-of-fire questions can be derived using this technique.
For more information, contact Doug DeGaetano at our Central Laboratory, 804-786-6800.
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A Technique to Facilitate
the Examination of Fabric Separations
Catherine B. Carlson, BA, and Elmer Gist, Jr., MS
Paper presented at the 25th Anniversary Meeting (1998) of
the Mid-Atlantic Association of Forensic Scientists (Rockville,
MD)
This presentation is a review of the forensic examination of fabric separations and a specific related problem area. A technique to facilitate the examination of fabric separations is the use of tape to secure the fabric edges. The technique is particularly useful in physical matching of fabrics. Several types of tape were tested on a variety of fabric separations. One type of tape was superior, with minimal distortion to the fabric edges.
For more information, contact Kay Carlson at our Western Laboratory, 540-561-6600.
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