You may have seen the case of Jane Mixer, who was thought to have been a victim of John Norman Collins aka The Co-Ed Killer. This has been profiled on numerous shows including Dateline (or was it 48 hours?), Cold Case Files and Infamous Murders. She was a Michigan nursing student who was killed in 1969 and her body placed in a cemetery on top of a grave.

After several decades had passed, DNA testing was done on a scarf of Mixer's, which produced very interesting results indeed. 2 male donors were supposedly identified: The first was John Ruelas, who is a convicted killer, but was only 4 years old at the time. The second was that of Gary Leiterman. Leiterman did live in the area in 1969, but hadn't had any run-ins with the law until literally days before he was charged with the murder of Mixer: He had passed a forged prescription for painkillers: he became addicted to them during a bout with kidney stones. His DNA was entered into the database and produced a hit. A jury found him guilty and he was given life without the possibility of parole.

However, some believe the DNA testing was contaminated due to the presence of a 4 year old's DNA supposedly being found on the scarf.

Does anyone have any theories on this? I think there might be a chance Leiterman is innocent. After all, the LE has really bungled this one, falsely attributing it to Collins, and then there's the situation with the then 4 year old Ruelas's DNA being found on Mixer's body. I think this case was really bungled.

I've read about this case a couple of times over the years. I remember the strange situation about the DNA findings but forgot what the explanation was as to why that man's blood was at the scene when he was only 4 years old. It seems like one theory to explain it was that maybe Jane was murdered by the 4 years old's uncle and the child was at the scene?

I don't know, I don't think so. I don't think they've ever answered that question. I know the uncle was investigated by LE but cleared. The whole case doesn't make sense, IMO.

I don't know much about the case beyond the CCF episode, but possible explanations I thought of were poor matching methodology, poor sample comparison, or a combination of the two. It just feels like a bungle to me. I think Ruelas' DNA might not have been on that scarf at all.

I also think it is probably purely coincidental Ruelas became a murderer later in life.