A dangerous secret spans from a deadly Monaco arson to a murder plot in New Mexico.

Jurors who heard the evidence in the Kouri Richins case speak out about what led them to convict her, including what they believe motivated the crime and why they reached their verdict.

Photos discovered on an old cell phone help solve the disappearance of a 14-year-old girl.

When a widow is found dead below a staircase in her Beverly Hills mansion, detectives search for answers.

A dream romance ends in murder when a woman falls for a stranger.

Nearly 41 years after a New York teen's murder, a surprising breakthrough brings new answers.

Renard Spivey, the TV bailiff who was accused of murdering his wife, opens up about the trial, his wife and more.

A toxic couple orchestrates an elaborate plan to kill a mother. "48 Hours" correspondent Peter Van Sant reports.

When a mother vanishes, her daughter is desperate for answers; decades later, a secret grave solves the mystery.

"Survivor" contestant Joe Hunter says his sister, whose death was officially ruled a suicide, was murdered.

A burglary leads investigators down a dark path, ending with a poisoned sweet treat.

The case of 17-year-old Benjamin Elliott, whose defense team says he was sleepwalking when he fatally stabbed his twin sister.

A preview of the case of a high school softball coach accused of recruiting a former player to kill her ex-boyfriend.

When a Michigan mother and businesswoman goes missing, her family is convinced she was murdered, but know that without a body or physical evidence, it would be difficult to prove.

After her husband is found with a fatal injury at the foot of the stairs, a woman is accused of murder and fights to clear her name.

Denise Huskins Quinn and Aaron Quinn share how they worked with law enforcement to help uncover additional crimes committed by their attacker, helping to bring justice to other victims.

Convicted killer Austin Herbst speaks out about murdering his father.

After a wife calls 911 to report her husband missing, police discover his lifeless body in his car, parked inside a corporate parking garage.

A young woman mourns her uncle's murder and questions whether the convicted killer was the only one involved.

Investigators initially believe a 15-year-old Montana girl's mysterious death was a tragic accident, but her family suspects something more sinister.