Latent Prints

The primary function of the section is to develop and recover latent prints from items of evidence, compare them to known exemplars and conduct database searches.

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Development techniques routinely employed by the section include:

  • Amido Black (protein enhancer for blood prints)
  • Alternate Light Sources (used to visualize inherent luminescence and fluorescent dye stains)
  • Gentian Violet (skin cell stain used on adhesive surfaces)
  • Ninhydrin (reacts with amino acids in sweat, used to process porous surfaces)
  • Cyanoacrylate Ester (super glue fuming of non-porous surfaces)
  • Dye Stains (MBD, Rhodamine 6G and Basic Yellow 40 are used to enhance prints after exposure to super glue fumes)
  • Powders

Latent fingerprints or palm prints that are determined to be sufficient quality are searched in the Virginia Automated Fingerprint Identification System (AFIS), which is administered by the Virginia State Police and/or the FBI Next Generation Identification (NGI).  If a “hit” occurs, the examiner performs a comparison of the latent print to the exemplar in the AFIS archive and determines if an individualization can be effected.  If an individualization is not effected the latent print will be registered in the unsolved latent database.  As new fingerprints and palm prints are entered into the system, they are automatically searched against each latent print in the unsolved latent database.

The section currently utilizes Mideo Systems Inc. LATENTWORKS to document the analysis, comparison, evaluation and verification of latent prints.