inside craig titus and kelly ryan's home.police say it began with kelly zapping melissa with a taser gun and using this kind of ticker tape from the gun itself. cops claim they were able to trace each time the taser was used. >> we knew the exact moment in time that the taser was fired five times. that time matched up with the time that craig titus was on his cell phone. so we believe that craig titus was in another room, not with melissa and kelly, o'kelly says after enduring 50,000v of electricity, tiny melissa had to fight off titus 242 pounds of pure muscle. >> in a violent rage. >> there's a bathrobe tie that was around her neck. there was also speaker wire that was wrapped around her neck as well. at autopsy, there was evidence of strangulation possibly being involved. her entire head was encircled with duct tape. >> the coroner's report also reveals a toxic level of morphine injected into melissa's leg. titus and ryan tell cops they did not kill melissa, claiming she injected herself, causing a fatal overdose. >> that