-41. >> but for hile, the dna results raised a red flag. >> back in 1983, the lab technician, daniel gregonis that he had consumed a-41 during his testing. now gregonis was asked to make sure that a-41 still existed. we have a photograph of the envelope that shows the date that he took it out and when he resealed it. so we know that he had a-41 on his person for 24 hours before he returned it. he'd also had nearby, the lab, the vial of kevin cooper's blood that was taken from him when he was arrested. >> contrary to gregonis' original testimony, the state now reported there was enough of a-41 for additional dna testing. results from the tan t-shirt also changed drastically. at the original trial, the tee shirt was only shown to have doug ryen's blood on it. >> when the tee shirt was tested at this time, there was additional blood located on the upper part of the tee shirt, across the chest that had not been noticed or photographed or even reported previous to this time. >> cooper's defense argued that the new blood on the t-shirt and the newly discovered blood s found on a-41 could only have

daniel gregonas. >> you test something and you don't know what the other person's blood is who you're trying to see whether it's that person or not but gregonisuntil he had his blood type. >> he originally found a-41 did not match kevin cooper but then he changed notes to show that it did. >> so, in fact, the testing actually showed that the blood drop was not from somebody with kevin's blood type. >> other evidence, prosecutors claimed linked cooper to the murders was a bloody shoe print on the ryen's bed. >> kottmeier claimed that these were tennis shoes bought and sold only to prisons. in fact, it was a stylish shoe, very common tennis shoes with a very common shoe print. >> the question now is whether these were innocent mistakes by investigators or something more. norm hile was about to learn that before they turned their attention to cooper, police had been given other solid leads, including from the sole survivor. >> 8-year-old josh ryen was able to communicate to staff at the hospital that the people who had attacked him and his family were three white men. in fact, a picture of kevin cooper was on television and he looked up and he s