20/20 on OWN

The investigation into the 2003 murders of four recent high-school graduates in a quiet Texas suburb.

The investigation into the abduction-murder of a 7-year-old girl in Orange Park, Fla., is related.

The case of Aaron Vargas, who was sentenced to nine years in prison after pleading guilty to voluntary manslaughter for the 2009 slaying of a man he claimed sexually abused him as a child.

The story of Brittney Bergeron, who survived a vicious assault at age 10 that left her a paraplegic.

The investigation into the 2006 disappearance of Nina Reiser, a Russian doctor who had married American computer engineer Hans Reiser in 1999, is recounted. At the time that she vanished, the two were in the midst of a bitter divorce and custody battle.

The case of Ramon Salcido, who went on a murderous rampage in Sonoma County, Cal., in 1989. He wounded two and killed seven, including his wife and two of his three daughters.

The Faylene Grant case is detailed. The Arizona woman, who drowned in her bathtub in 2001, seemingly predicted her premature death. Her husband Doug, initially charged with first-degree murder, was convicted of manslaughter in 2009 and sentenced to five years in prison.

The cases of three Western women who disappeared while in Japan.

Part 1 of 2. The case of so-called "black widow" Stacey Castor, whose first husband died of an apparent heart attack and second husband seemingly killed himself.

Conclusion. The case of so-called "black widow" Stacey Castor, whose first husband died of an apparent heart attack and second husband seemingly killed himself.

The case of fashion designer Anand Jon, who was convicted of sexual assaulting would-be models, is detailed.

The case of a chiropractor whose fifth wife died from a blunt-force head injury in 2010.

The story of Katie Piper, a British model and TV host who was disfigured in March 2008 when a man hired by a former boyfriend threw sulfuric acid in her face.

A feud between neighbors results in murder.

The story of Terri Jendusa-Nicolai, who survived a vicious assault by her former husband. He attacked her with a baseball bat, bound her and stuffed her in a garbage can, which he left in a storage unit.

Ordinary people who helped solve crimes. Included: a daughter exposes a dark family secret; a woman who strives to learn how her husband really died; and four women who put their lying lover in jail.

Two men join forces in an effort to find their missing daughters.

A kindly man hits the lottery for millions but is unfortunately oblivious to a swindler who is conspiring to take his money—and possibly his life. Also: after a series of arsons in a small town the residents are shocked to find out who was behind them. 

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

The story of 16-year-old Skylar Neece, who was killed by her two best friends in 2012.

A tumultuous romance leads to fiery passion and, in time, murder.

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

The Trayvon Martin case is examined. Also: the escape of three women held for years by Ariel Castro in Cleveland.

An Internet prank turns deadly on Long Island.

A report on two separate murder cases that investigators suspect were inspired by the TV drama "Dexter."

The case of a Nashville woman who was convicted of strangling her husband to death in 2010.

Two stories of love, betrayal and murder.

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

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

The drowning death of a young girl may not have been an accident. Also: a spurned suitor turns violent.

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

A boy becomes the center of a rivalry between two teenage girls.

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

The story of a young man whose estranged father stole his identity and ruined his credit and reputation; and the case of an 18-year-old woman who killed her father.

The April 17, 2006, murders of Wayne and Sharmon Stock in Murdoch, Neb., is investigated.

The investigation into a 1985 triple homicide on the outskirts of Fayetteville, N.C, is chronicled. The victims were a military wife and two of her young daughters.

An alleged murder-for-hire plot in the Houston area is detailed.

A report on the murder trial of a suburban-Atlanta engineer charged with killing the husband of a coworker with whom he was allegedly having an affair. His defense of the shooting that took place outside a day-care center: insanity.

A report on a battle over a widow's will: Mary Ellen Bendtsen of Dallas gave her house to two antiques dealers—not her family—shortly before her death in 2005. Also: a look at the facts (and the mystery) behind the 2006 movie "The Night Listener," including an interview with Armistead Maupin, who cowrote the screenplay.

The case of James Arthur Ray, a self-help guru and motivational speaker whose 2009 "Spiritual Warrior" retreat in Arizona resulted in the deaths of three people in a sweat-lodge exercise gone wrong.

The case of Josh Powell, who was suspected in the 2009 disappearance of his wife; and then killed himself and his two sons in 2012. Also: the story of an Arkansas businessman who reportedly fell into the Little Red River during a family vacation in 2008; and resurfaced six months later in South Dakota, where he was using a different name.

The investigation into an attack on a Maine couple while they were asleep in bed is recounted. The husband, management consultant Jeffrey Dolloff, was beaten with a baseball bat; and the wife, yoga instructor Linda Dolloff, was shot. 

A report on the 2001 murder of millionaire Ted Ammon in his East Hampton, N.Y., mansion includes a conversation with his convicted killer, Daniel Pelosi.

The case of Gabe Watson, whose wife Tina died while scuba diving in 2003 Australia. He pleaded guilty to manslaughter in Australia and served 18 months. He was also charged with murder in their native Alabama, but was acquitted. 

A report on a 2007 NASA love triangle that almost turned tragic; and an interview with parents upset by online photos of the car accident that killed their daughter.

Autistic therapy turns a child against her parents; a father struggles to protect his daughter from his ex-wife.

A teenage love story gone tragically awry is detailed.

The Steve Nunn case is examined. The son of a former Kentucky governor, he seemed to have a bright political future. That changed in 2009, however, when he was charged with murdering his former fiancée, Amanda Ross. Two years later, he pleaded guilty in a deal to avoid the death penalty. 

The case of a serial rapist who found his victims through a popular dating Web site.

Interrogation tactics employed by the police are examined.

A true-life "War of the Roses" marital horror story about a Connecticut advertising executive who kidnapped his ex-wife in 2009 and held her hostage in the home they had shared. He also burned down their beach house. 

An eighth-grader's brutal crime against a fellow classmate; a teenager's role in a grisly Internet scheme.

An interview with Dharun Ravi, a former Rutgers University student convicted of invasion of privacy and bias intimidation following his roommate's suicide in 2010. Also: a report on a Web site created to bring news to small-town America.

A look at murder-for-hire plots foiled by federal agents who went undercover as hit men. Included: a man who wanted to off his wife; a soccer mom who was gunning for a romantic rival; and a drug dealer who sought to kill an informant.

A family man mysteriously vanishes, only to re-appear years later; a high school honors student's sexual relationship with a fellow schoolmate lands her in jail.

The story of Tyler Hadley, a Florida teen who threw a house party after killing his parents. Also: an intoxicated teen in Virginia is fatally shot by a home owner when he mistakes a neighboring house for his own.

Part 1 of 2. An interview with California kidnapping victim Jaycee Dugard, who was abducted in 1991 by Phillip and Nancy Garrido and held for 18 years.

Conclusion. An interview with California kidnapping victim Jaycee Dugard, who was abducted in 1991 by Phillip and Nancy Garrido and held for 18 years.

Part 1 of 2. The discovery of an unconscious, brutally beaten woman in an empty Florida cul-de-sac is investigated.

Conclusion. The discovery of a brutally beaten woman in an empty Florida cul-de-sac is investigated.

Cleveland kidnapping survivors Amanda Berry and Gina DeJesus discuss the decade they were held captive by Ariel Castro.