The sister of Karen Caughlin, Marylou Schwemler, seen here with her husband, holds in her emotions as the OPP screen a new video that investigators hope will jog memories about a 40-year-old murder case. The 14-year-old Caughlin went roller skating with friends at the Rose Gardens in Point Edward and was expected at a friend's house on Brock Street by 1 a. m. She was dropped off at 12:50 am but didn't make it inside the home. Nine hours later, her battered body was found on Plowing Match Road outside of Petrolia. Her killers have never been found. To view the video go to http://youtu.be/4qaWsh01osM