A study by the Urban Institute released on Monday found that at least 38 individuals convicted of homicide or rape could be exonerated on the basis of DNA testing. The study is reportedly the first to examine how much exoneration could result from Virginia's archive of biological samples. Some of those samples are decades old.
Researchers in the study looked at the results of DNA testing of samples archived from 635 cases of murder, sexual assault and non-negligent manslaughter between 1973 and 1987. During those years, DNA testing was not a widely used tool in investigating criminal cases. Researchers mostly looked as samples containing semen and blood.
Among the 38 cases categorized as exoneration possibilities, five men have already been positively ruled out as perpetrators of sexual assault convictions as a result of the DNA testing. In those cases, the convicted person was ruled out since the profile was shown to be from a male who was not the convicted person. Thirty three convicts apparently had a DNA profile that did not match the suspect and which matched a known person who was neither the convicted person nor the victim.
The report noted that there may be certain limitations in the findings. In two-thirds of the cases, for instance, the samples didn't contain enough DNA for testing, which may mean the number of false convictions is actually higher. Samples didn't always come with enough information to be able to put the samples in context and determine their value.
In our next post, we'll continue looking at this topic.
Source: Washington Post, "Policy group's study shows at least 38 wrongful convictions likely in old Virginia cases," June 18, 2012