The Craigslist Killer’s Police Interview (2009)

Not technically a documentary but “The Craigslist Killer’s Police Interview” is a fascinating first encounter audio recording between the Boston police department homicide detectives and suspected murderer Philip Markoff...  Police later determined that Markoff still had the blood of his victim — Julissa Brisman, who advertised erotic massage services on Craigslist — on his shoes during the interview.

“Boston Police used electronic sleuthing — including IP address snooping, cell-phone tower triangulation, and a subpoena of Markoff’s Facebook account — to hunt the killer down. On August 15, 2010, Markoff committed suicide in Boston’s Nashua Street Jail, where he was being held in custody awaiting trial…”  WIKIPEDIA