The Man Who Knew Too Much Dateline NBC : Season 25 Episode 7

California, 2000: Michelle O'Keefe is found dead in her car in a parking lot. Raymond Lee Jennings, a security guard patrolling the parking lot, says he saw her after she was shot. He seems to know things only the killer would know. But, due to lack of any forensic evidence (and even blood evidence that seems to rule him out), he isn't arrested until nearly six years later. A cautionary tale on the recent trend of too-heavy reliance on circumstantial evidence follows.