And Now, The DNA Evidence

Hollywood has done a great job trumpeting the benefits of DNA – the double-edged sword that can free a wrongly convicted inmate and force a killer to face his or her legal fate – but the reality of DNA's impact on the criminal justice system is quite something else.

USA Today reports half of the states still do not have requirements mandating the preservation of DNA evidence. Proposed laws to implement or ramp up DNA databases – including, in some cases, collecting DNA from individuals who have not been convicted of crimes – have run into obstacles including concerns about costs and civil liberties.

Even when DNA databases do exist – and contain matches to potential suspects in criminal cases – there can be problems, according to a 2006 study published in the Journal of Law, Medicine and Ethics. Researcher Frederick Bieber reported then that databases have been helpful in both identifying suspects and ruling them out – saving investigators time and money – but administrative and crime lab logjams can cause delays in searches of databases, and even after potential DNA matches were found, hundreds of matches languished without any follow-up by law enforcement or prosecutors.

According to The Innocence Project, there have been 218 cases since 1989 in which DNA led to official declarations that individuals were not guilty of the crimes for which they were previously convicted. On average, they had spent about 12 years behind bars; sixteen were on death row.

Public confidence in DNA evidence is high. A 2005 Gallup poll found 85 percent of participants said they think it is either completely or very reliable. And a 2003 Time/CNN/Harris Interactive poll found 82 percent who said they were either very concerned or somewhat concerned that lack of funding sometimes prevents DNA testing from always being carried out in death penalty cases.