In this episode, Louise digs further into a potential new line of enquiry. She meets with a former detective superintendent who says there could be a link between Linda and convicted double murderer Christopher Halliwell, who killed two women in the Swindon area. Could Linda have been another one of his victims? She also arranges for Glyn Razzell to take a polygraph test in prison while Inside Justice experts pore over the forensic evidence that was so crucial in Glyn's conviction. His wife Linda's blood was found in the boot of the car her estranged husband was driving on that day. Glyn has always maintained the blood was planted by Linda and that she staged her own disappearance. Will the experts agree this is a possibility or is the conviction sound?