She survived a vicious attack in her kitchen. Her case helped catch a college student’s killer. In a new interview for tonight’s 20/20 Season Premiere, Rosemary Diskin shares with Deborah Roberts how her son helped save her. 20/20 'The Salem Strangler' season premiere starts tonight, Friday, Sept. 25th, at 9/8c on ABC. Stream on Disney+ and Hulu. #Investigation #TrueCrime #ClaireGravel #ABC2020