Starting this year, every convicted felon in Pennsylvania has been required to provide a tissue sample for DNA testing, says the Pittsburgh Post-Gazette. The goal is to see whether the convict’s genetic profile matches the DNA from any of nearly 120,000 unsolved cases in a national database. This procedure, which started on a smaller scale in 1995, so far has matched 321 Pennsylvania prisoners to previously unsolved cases, said Christine Tomsey, Pennsylvania State Police DNA Crime Lab director.
The law does not require that the prisoner’s DNA be compared to evidence from his original case to make sure he was properly convicted. There are practical reasons why that might not be a good idea, experts say. It would place an extra burden on an already overloaded system. When the law was rewritten to require every felon to provide a DNA sample, the state lab quickly went from having no backlog to falling behind on 49,500 specimens. Criminologist William Thompson of the University of California at Irvine, said another reason not to test felons’ DNA automatically against evidence in their original crimes is that many know they are guilty and wouldn’t ask for such a test if it were up to them.