Forensic Files - Season 9 Episode 3 : In Harm's Way 2011

An Alaskan police officer found a woman's body while on routine patrol of a public park. The victim had been stabbed to death and, during the autopsy, the medical examiner preserved the portion of her rib cage which sustained the fatal wound. A knife thought to be the murder weapon turned up days later, two thousand miles away. Forensic scientists now had an opportunity, which seldom occurs, to compare the microscopic marks on the presumed murder weapon with the marks on the victim's bone.