FBI Evidence Response Team members work with latent prints, Washington DC, 2012. The Evidence Response Team Unit (ERTU) provides traditional and hazardous evidence collection capabilities to FBI field Evidence Response Teams (ERTs), Hazardous Evidence Response Teams (HERTs), Hazardous Evidence Response Components (HERCs), Underwater Search and Evidence Response Teams (USERTs), and law enforcement partners by offering forensic training, resources, and expertise in support of the FBI's investigative priorities. Although the word latent means hidden or invisible, in modern usage for forensic science the term latent prints means any chance or accidental impression left by friction ridge skin on a surface, regardless of whether it is visible or invisible at the time of deposition. Electronic, chemical and physical processing techniques permit visualization of invisible latent print residues whether they are from natural sweat on the skin or from a contaminant such as motor oil, blood, ink, |