"Keep hope, and we hear and see you." The family of a slain Massachusetts student spent nearly four decades seeking justice after her June 1986 murder. Our newest "20/20" examines the mysterious case, how Claire Gravel’s family continues to honor her and the message they have for other families of unsolved cases. Stream 20/20 ‘The Salem Strangler’ now on Hulu and Disney+ (S49, E01).

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

Deborah Roberts investigates how police solved a Massachusetts student's murder. Watch the 20/20 Season Premiere 'The Salem Strangler' tonight (Sept. 25th) at 9/8c on ABC. Stream on Disney+ and Hulu. #ABC2020 #Investigation #ClaireGravel #Mystery

The college student was last seen at a bar the day before her body was found, sparking a 40-year investigation into her murder. 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

20/20 SEASON PREMIERE: A deadly mystery of a woman strangled…and then, another woman is attacked. Watch the Season 49 Premiere of 20/20 'The Salem Strangler' - tonight (Sept. 25th) at 9/8c on ABC. Stream on Disney+ and Hulu.

NEW 20/20 SEASON PREMIERE: The 20-year-old college student was last seen when her friend dropped her off after a night out in downtown Salem. Now, Claire Gravel's brother speaks with Co-Anchor Deborah Roberts about learning she vanished. 20/20 'The Salem Strangler' premieres Friday, Sept. 25th at 9/8c on ABC. Stream on Disney+ and Hulu. #Investigation #TrueCrime #ClaireGravel #ABC2020

A deadly mystery of a woman strangled…and then, another woman is attacked. Watch the Season 49 Premiere of 20/20 'The Salem Strangler' - Friday night (Sept. 25th) at 9/8c on ABC. Stream on Disney+ and Hulu.

The extraordinary steps one woman took to uncover the truth about her friend's disappearance, including going undercover in a tense sting operation to secretly record her ex-husband.

ALL-NEW 20/20: Forbidden love and a deadly mystery. How one brave woman went undercover to unravel the shocking truth. The all-new 20/20 “Mr & Mrs Murder” premieres tonight (Sept. 18th) at 9/8c on ABC. Stream on Disney+ and Hulu.

She relentlessly pursued the truth - uncovering a dark web of lies, betrayal and murder behind her friend’s disappearance.

The Sunshine State carries dark secrets. Get ready for alligators and infidelity, and that’s just for starters on this week’s all-new 20/20.

Deborah Roberts and Dr. Darien Sutton unpack some 20/20 cases where true crime and medicine collide. Listen now wherever you get the 20/20 Podcast. #2020Podcast #TrueCrimePodcast #TrueCrime #MedicalMystery

Forbidden love and a deadly mystery. How one brave woman went undercover to unravel the shocking truth. The all-new 20/20 “Mr. & Mrs. Murder” premieres Friday, Sept. 18th at 9/8c on ABC. Stream on Disney+ and Hulu.

STARTING SOON: Mistrial declared in the trial of Lindsay Clancy. What happens next? Watch a special edition of 20/20 tonight at 9/8c on ABC.

Lindsay Clancy's trial captured the public's attention, highlighting the challenges of prosecuting mothers with mental illness and shedding light on a lesser-known mental health condition known as postpartum psychosis. Watch a special edition of 20/20 tonight at 9/8c on ABC.

TONIGHT: Mistrial declared in the trial of Lindsay Clancy. What happens next? Watch a special edition of 20/20 tonight at 9/8c on ABC. abcnews.link/WH99yIl

The Massachusetts mom and the killing of three young children. Now, the breaking special, “The Trial of Lindsay Clancy,” premieres tonight at 9/8c on ABC. Stream next day on Disney+ and Hulu.

“That tranquil life was interrupted in the worst possible way.” @DebRobertsABC takes us to Hobe Sound, Florida, for this week's 20/20 mystery. It was the spring of 2016. 30-year-old mom Tricia Todd never arrived to pick up her daughter from the babysitter. Tricia’s mother said she knew right away that meant something was wrong. Watch 'The Hungryland Homicide' encore tonight (Sept. 4th) at 9/8c on ABC. Stream on Disney+ and Hulu (S46, E26).

A mysterious true crime, a young mother murdered, and the stunning details of what happened next. Watch 20/20's 'The Hungryland Homicide' encore tonight (Sept. 4th) at 9/8c on ABC. Stream on Disney+ and Hulu. (S46, E26)

Celebrate Dolly Parton's life, music and legacy. Rare interviews with Dolly herself and reflections from those who knew her best. Watch an encore presentation of our 20/20 tribute - Sunday at 10/9c on ABC. #DollyParton