Dateline: Unforgettable

As an experienced diver, Shelley Tyre had been looking forward to an easy dive in Tortola to explore twin ship wrecks with her husband, David Swain. Tragically, she would never return from the trip.

Dan Wozniak needed money for his upcoming wedding, so he betrayed two friends to get it.

A steamy affair between paralegal Kandi Hall and her married boss, Emmett Corrigan, ended violently in a Walgreens parking lot in March 2011. 

Dalia Dippolito's reaction to her husband's "murder" was even caught by the show Cops, as they were following the Florida police department at that time.

Was Lars Itzo a grieving husband who made a horrific mistake when he shot wife Debbie Kelly in the chest or a calculated killer? 

She thought it was the vacation of a lifetime, but  Micki Kanesaki would never survive the Italian cruise with her ex-husband. 

He claimed to be a successful doctor, but "Dirty John" Meehan was carrying some dark secrets. 

Ben Novack Jr.'s brutal death would reveal a heartbreaking betrayal and uncover another calculated murder once thought to be an accident.

“You know I felt so loved and I felt so treasured and I felt so worthy and you know at that moment I thought, well, it was all worth it,” suburban mom Toby Young said of her whirlwind romance with convicted killer John Manard.

Did a bitter feud over the Maryland house Scott Horn had loved lead to his death?