Watch Confessions of the Boston Strangler (2014) : Full Movie Online Free This two-hour documentary special for Investigation Discovery sends viewers back to a time when no woman in Boston felt safe. The city finally felt a sigh of relief when, in a recorded confession, Albert DeSalvo admitted to his savage rampage and the first known serial killer in America was put behind bars. But decades later, compelling DNA analysis revealed that DeSalvo may not in fact have committed the crimes.