Watch Sadisflix. Boston Strangler: The Untold Story is an intense true-crime thriller about Albert De Salvo, a wise cracking, small time criminal with an unrelenting sex drive, who ultimately falsely confesses to being the strangler that wreaked havoc in Boston during the early sixties. Guided by his manipulative cell mate, who knows more about the murders than he reveals, they devise a plan to gain all of the notoriety from the killings and the money from the reward. Meanwhile, Detective John Marsden, searches out the truth certain that they were not committed by one man. Fighting the bureaucracy of the day, Marsden lets his emotions get the best of him as he follows the trail of the murders.