"Forensic Files" Marked for Life (2005)

Synopsis (CONTAINS SPOILERS): El Segundo, California, 1957. Two couples are making out inside a car when a man approaches with a gun pointed at them. He robs them, rapes one the women, flees in their car, crosses a red light, is stopped by a police car, gets out of the car, shoots both policemen. He escapes after being hit by a bullet from one of the policemen. Both policemen die. The car is found, there are two partial fingerprints on the wheel, they are of the same finger, they are joined to form a complete fingerprint, no match is found anywhere. In 1960, a man finds the gun in his back yard. They locate the place of purchase, and the form filled and signed by the purchaser. No one by the name in the signature has a matching fingerprint. In 2002, a woman reports on her uncle who was bragging about being the perpetrator. His fingerprint doesn't match the one they had. They decide to scan their entire database since it's all done by computer now. They find a match, it's a guy arrested for burglary in 1956, he didn't come up in 1957 because the data from South Carolina was not in the national database then. They find the guy, he does not have any criminal record after that 1956 crime, he has a wife and kids now. He is arrested, his handwriting is compared to the one in the form the killer had filled at the arms store, they're nearly identical, he still has the mark from the bullet wound. He pleads guilty.