Latent evidence from crime scenes is processed and submitted to the Latent Print Unit for examination. A latent print is a chance reproduction of a finger or palm print, often invisible until physical or chemical development, that may be left behind by direct contact with an object.
Latent Print Unit personnel encode and search suitable prints against one or more database systems. Available systems include the Metropolitan Nashville Police Department Automated Fingerprint Identification System (AFIS) database, which includes the fingerprints and palm prints of adults and juveniles generated from Davidson County arrest records and Metro Nashville Police Department personnel. The Latent Print Unit also has the capability to search AFIS quality impressions in the State of Tennessee’s AFIS database and the Federal Bureau of Investigation’s Next Generation Identification (NGI) database, to include fingers and palms. Latent prints that are not identified are generally registered to the database(s) in which they are initially searched, and registered prints are automatically searched against all new arrestee fingerprints and palm prints. Latent prints that are not suitable for database searches can be manually compared to the fingerprints (and palm prints) of individuals submitted by investigators upon request.
Standard equipment for analyzing latent impressions includes magnifying devices and large, high-resolution computer monitors. As personnel analyze evidence and conduct comparisons, observations are documented in a Digital Evidence Management Software. The Laboratory Information Management System is utilized to track chain of custody and electronically report findings.
