"Blood, Lies & Alibis" (Mon., 9 p.m. ET on ID) delved into a 2002 case from Canada that initially stumped police. An 18-year old young woman went missing, and police weren't able to find any viable leads. Their only suspect was her boyfriend, who had an alleged history of violence, but even that lead didn't go anywhere.
A year later, the family got an anonymous note telling them that their daughter was dead. This escalated the investigation, leading the police to investigate it as a homicide. They set up an elaborate sting operation on the boyfriend -- still their best suspect -- and fooled him into a full confession.
Undercover officers posed as organized crime operatives offering him a chance to rise in their ranks, but only if he confessed to a true crime. The boyfriend opened up in graphic detail and wound up serving a life sentence in prison.
While authorities were never able to determine who sent the letter, it proved to be the turning point in the case.
New true mysteries and crime on "Blood, Lies & Alibis" every Monday at 9 p.m. ET on ID.
TV Replay scours the vast television landscape to find the most interesting, amusing, and, on a good day, amazing moments, and delivers them right to your browser.
RELATED ON HUFFPOST:
HuffPost Entertainment is your one-stop shop for celebrity news, hilarious late-night bits, industry and awards coverage and more — sent right to your inbox six days a week. Learn more