>> beaumont called in specialized military and law enforcement units to search. >> so rather than give up, it occurred to me that obviously larry hall knew. >> beaumont needed answers and turned to an unlikely source to get them. he needed someone to befriend larry hall. someone charismatic. someone on the inside. larry beaumont needed jimmy keen. beaumont had sent both keen and hall to prison. now he hashed a risky plan that would bring them together. keen was ten months into his sentence when beaumont brought him in to talk. >> scared me. i thought this was some trick. >> keen watched nervously as beaumont pushed a folder across the table. >> i open it up. the first thing i seen was a picture of a mutilated dead girl and i flipped the next page and there was a different mutilated dead girl. >> and there was a portrait of tricia reitler. >> at that moment i looked up at beaumont. he said, jimmy, we need you to help us with this case. >> beaumont wanted keep to go undercover to transfer from his low-security lockup to a dangerous prison. and to befriend alleged serial