there was more to this friendship. >> reporter: john and melissa sutton knew nothing. r and his girlfriend were still living with john. garrett kopp was still coming around. so, solid evidence or no, detectives decided it was time to act. they needed a confession to make their case. >> i told the investigate investigators, bring him to me. >> coming up a showdown with the killer. >> go in the back door, walk in, shoot him. >> reporter: case closed? far from it. when "blind justice" continues. stay with me, mr. parker. when a critical patient is far from the hospital, the hospital must come to the patient. stay with me, mr. parker. the at&t network is helping first responders connect with medical teams in near real time... stay with me, mr. parker. ...saving time when it matters most. stay with me, mrs. parker. that's the power of and. keith morrison: detectives larry belyeu and art nanni had a theory to explain the shooting of john sutton >> reporter: the detectives had a theory to explain the shooting of john sutton and the murder of his wife susan which was that chris