PCR DNA tests, Bloodsworth case, 1993. DNA testing is a technique employed by forensic scientists to assist in the identification of individuals by their respective DNA profiles. With the invention of the polymerase chain reaction (PCR) technique, DNA profiling took huge strides forward in both discriminating power and the ability to recover information from very small (or degraded) starting samples. Kirk Bloodsworth was sentenced to death in Maryland for the 1984 sexual assault, murder, and mutilation of 9-year-old Dawn Hamilton. Bloodsworth insisted on his innocence and no physical evidence linked him to the killing. In prison he learned about DNA profiling. Eventually his attorney, Bob Morin, with support from the Innocence Project, a nonprofit legal clinic formed to promote the use of DNA analysis to exonerate innocent prisoners, persuaded officials to compare Bloodsworth's DNA with the DNA of dried sperm found on the victim. The results exonerated Bloodsworth. He was freed from prison in June 1993, the first death-row prisoner to be exonerated by post-conviction DNA testing. As of 2011 there have been 289 post-conviction DNA exonerations in the United States.