The five-year investigation into the death of a retired corrections officer, who was killed by antifreeze poisoning, reveals multiple suspects.

The five-year investigation into the death of a retired corrections officer, who was killed by antifreeze poisoning, reveals multiple suspects.

A model with a checkered past goes under cover to reveal the truth about a cold case involving a romantic getaway on a boat that ended with a woman being lost at sea.

Full coverage of the series of shootings and bombings across Paris

Dateline NBC coverage of the terrorist attacks in Paris, France of November 13 2015

When detectives track down the killer of a Las Vegas cocktail waitress and mother, it becomes clear that the investigation has just begun.

Natalie Morales speaks to the mother of the teenage sexual assault victim from St. Paul's School; new details from both sides of the case, Owen Labrie's conviction and sentencing, and interviews with Labrie's friends and legal team.

Natalie Morales speaks to the mother of the teenage sexual assault victim from St. Paul's School; new details from both sides of the case, Owen Labrie's conviction and sentencing, and interviews with Labrie's friends and legal team.

The case of Johnny Hincapie, whose conviction for the 1990 murder of a Utah tourist in New York -- a case that represented a tipping point in the city's law enforcement -- was overturned after 25 years; a 29-year-old woman goes missing.

Daniel Villegas, 16, confesses to a double murder in El Paso, Texas, and is sentenced to life in prison. When a local businessman hears of the case 10 years later, his investigation leads him to believe the teen was coerced into a confession and wrongfully convicted.

Twenty-seven women who have accused Bill Cosby of assault get together to share their stories.

When a woman returns two days after being reported abducted, authorities believe it's a hoax until a similar crime forces them to take another look; twenty-seven women who have accused Bill Cosby of assault get together to share their stories.

Authorities take two years and three trials to solve the shooting death of the wife of an FBI agent in the kitchen of her family's Virginia home.

An arrest is finally made five years after a mother of four disappeared while she was close to her apartment in Montana.

Cathy Torrez was a beautiful, smart and responsible 20-year-old student. So why didn't she come home after work like she was supposed to?

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When Diane Kyne is found dead in her bedroom, competing stories emerge about which of the two most important men in her life may have killed her. One of the stories must be true – but which one? Dennis Murphy reports.

Stacey Schoeck, the Snellville, Georgia, wife and mother who hired a hit man to kill her husband on Valentine's Day