there was more to this friendship. >> reporter: john and melissa sutton knew nothing. opher 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. e from potentially deadly heartworm disease. the threat is everywhere. and it only takes one mosquito bite to transmit it. that's why you need to protect your dog with heartgard plus. just one real beef chew given once a month, every month, helps keep your dog safe all year long. test dogs for infection prior to use. in rare cases: digestive and neurological side effects have been reported. for more information contact your vet. get your dog out of hiding, ask your vet about heartgard plus. the vet's #1 choice. with a lot of other young couples. then we noticed something...stra

wasn't enough for john sutton.he waited for his son's long delayed trial he pursued with something like an obsession, a quest to regain his eyesight. and most people might have given up by then. can't do anything. live with it. >> not even close. >> not you? >> no. i won't take no for an answer. >> at some of the best hospitals in the country, sutton had been told there was simply nothing to be done. the bullet had destroyed his optic nerve. he would be blind for life. the bullets had permanently destroyed his optic nerve. john had heard about a landmark break through at harvard affiliated research institute in boston where a renowned researcher had regenerated the optic nerve in mice using stem cell therapy and drugs, human trials would be next. >> one step up. >> and so in march 2008, almost three years to the day after his son was arrested, sutton and his girlfriend kathy were on the cold rain-swept streets of boston on the way to an appointment at scapins. >> okay. there is a chin rest in front of you. >> a doc

who would want to hurt john and susan sutton? san dead and her husband clinging to life, detectives had questions for one possible suspect. teddy montodo, john's law partner and close family friend. just how close? investigators were about to find out. here again is keith morrison. >> >susan sutton was dead, shot five times and her husband was undergoing multiple surgeries to save his life. soon after the shooting, they had a potential suspect. john sutton's friend and law partner. >> he had a partner on the scene when the detectives god there. >> he told police he had been on the phone with susan and heard the unmistakable sound of gunfire and rushed with his gun to help. was that the whole story. they gave him a polygraph. it showed he had been deceptive and hiding something. >> what we learned was that he was having an affair with mrs. sutton. >> so, montodo hasn't been straight with him. but was he on the hook for murder? he was still deceptive and told them the affair was brief but that's not what the phone records showed. di