20/20 on ID

A boy becomes the center of a rivalry between two teenage girls in the opener of the crime documentary series.

Two missing daughters unite two fathers, who become citizen detectives to find them.

The crimes of Marcus Wesson, who controlled his family like a cult before their bloody demise, are detailed.

A young military wife and two of her daughters are murdered in their own home, and one toddler is spared from the killings.

The crimes of Philippe Padieu, who was convicted for knowingly exposing his unsuspecting lovers to HIV.

An Internet prank turns deadly on Long Island.

A minister's wife is found dead in her home. Police question whether it was suicide or murder, and the minister's mistress could be the key to solving the mystery.

The story of Rebecca Babcock, whose mother, Diane Downs, shot three of Rebecca's siblings in 1983, killing one of them

Two fathers travel to Italy to be reunited with their sons, but their efforts are impeded.

The 2006 killings of Wayne and Sharmon Stock in Murdock, Neb., and the subsequent investigation are discussed.

The ordeal of a high-school teacher who was kidnapped—along with her daughter—by a deranged former student is detailed.

A phony Internet romance, lies, deception and murder.

The case of Etan Patz, a 6-year-old boy who went missing in New York City in 1979, is discussed.

The murder of 15-year-old Leah Freeman, who was slain in Coquille, Ore., in 2000, is investigated.

Profiling Kelley Cannon, who was convicted of killing her husband in 2008.

A tale of love gone awry for a real-estate agent and a lounge owner culminates in murder.

Two tales of love gone wrong from Seattle and Missouri are detailed.

A young man's identity is stolen by his estranged father; a murder case in which an 18-year-old woman killed her father is detailed.

Girl drowns in a pool; her mother becomes a target, and this supposed accident becomes more

A report on two separate murder cases---one in Indiana, another in Edmonton---that investigators suspect were inspired by the TV drama "Dexter."

The discovery of a woman's naked and beaten body begins a mystery of dead ends, but a determined investigator refuses to give up on his search for the truth.

The discovery of a woman's naked and beaten body begins a mystery of dead ends, but a determined investigator refuses to give up on his search for the truth.