A Powerful Tool Instead of relying solely on intact fingerprints to identify suspects, scientists now use deoxyribonucleic acid, more widely known as DNA, which contains chemical building blocks that vary from person to person, to identify individuals with virtual certainty. The latest technology can create a genetic profile of a suspect using only the saliva left on an envelope or a hair in a victim's hand. The FBI is currently in the process of building a national databank of DNA profiles similar in scope to its national fingerprint file. Although only 14 states are now linked to the national database, the FBI aims to link all the states in a year or so. Already, all 50 states collect DNA samples from convicted sex offenders.
Some states collect DNA from all violent convicts, and four others collect samples from all felons.
And the science isn't just putting criminals away. So far, DNA evidence has exonerated scores of wrongly convicted defendants. The Innocence Project, a program run by defense lawyers Peter Neufeld and Barry Scheck that challenges convictions with DNA evidence, has helped free more than three dozen people from prison. Cold Cases DNA samples have helped solve crimes that had no other investigative leads. During the last six months in Virginia alone, DNA has helped solve 33 rape and murder cases that previously had no suspects.