Thursday

On valentine's day weekend 1999, three tourists from yosemite national park disappeared and were found murdered a month later. At the time, handyman cary stayner was questioned but released due to lack of evidence. However, when another missing woman was found dead in yosemite park, authorities were able to pin stayner with all four murders.

In 1972, a postal worker is found brutally murdered in his San Diego apartment. Investigators wade through suspect after suspect, from close friends to hardened criminals. Thirty-seven years later, old evidence points them to their killer.