A 12-year-old girl goes missing on her way to school in Oregon City, Oregon. The police investigation offers little in the way of leads. Then, a second girl disappears.

The discovery of four women's bodies on Gilgo Beach was just the beginning. But who is the Long Island Serial Killer? Investigators uncover multiple suspects and shocking theories, as they race to capture this prolific killer before he strikes again.

After a young couple goes missing, detectives find a clue leading them to a strange storage container in the middle of 95 acres, and what's inside unlocks the secrets of a monster hiding in plain sight.

[The Keddie Murders] A mother and three teens are murdered in the remote town of Keddie, California. Despite a trail of suspects and illicit activity, no one was ever brought to justice. But recently discovered evidence may be the key to finally cracking case.

[Los Angeles Serial Killer] A lone survivor is the only witness who can help police track down a serial killer known as the Grim Sleeper, who preys on women in South Central Los Angeles. After decades of searching, police hone in on an unlikely suspect.

In the 1970s, a serial rapist is on the loose in northern California. As his reign of terror over the community wanes, police discover he isn't just a serial rapist, he's a serial murderer who has been killing people all over California.

One summer night in 2007, the Petit family is woken up by two strangers in their quiet Connecticut home. Suddenly, these four family members find themselves being held hostage and in a fight for their lives.

In 1988, a young woman is found murdered in her Modesto, CA, home, leading police to investigate the strife and infidelity in her marriage. A surprising witness eventually comes forward.

When a widower and father of three is found murdered outside his Long Island home, police have reason to look into shady business dealings as a possible motive. Then, a tip leads to three unlikely suspects, exposing dark family secrets.

Two days before the new millennium, the Freeman family trailer is burned to the ground. The couple's remains are found with bullets to the head, but their teenage daughter and her friend are missing.

[Mystery in Texas] In 1995, 16-year-old Adrianne Jones is found shot to death in Grand Prairie, Texas. A model student and athlete, there seems to be no reason for her death. Police investigate boyfriends, neighbors and local troublemakers, but don't have any strong suspects. The case grows cold, until nine months later when a game of Truth-or-Dare leads to a startling confession and an over-achieving relationship that went murderously awry.

When a young family vanishes from their Southern California dream home, friends and family are left with dozens of unanswered questions. Authorities suspect they fled the country, until an unlikely source uncovers the truth.

Art imitates life when Cambodian genocide survivor Dr. Haing Ngor wins an Oscar for his role in the film The Killing Fields. But when he's gunned down, the LAPD investigate a web of political intrigue, revenge, and street gangs to uncover the truth.

In July of 2010, NBA star and family man Lorenzen Wright goes missing outside of Memphis, TN. When his dead body is discovered in the woods, investigators find that this case is far from a slam dunk.

On a snowy night in January 1980, college student Helene Pruszynski disappears after reaching her final bus stop. When her body turns up in a snowy field, police launch a long and frustrating investigation that pushes family and detectives to the brink of hopelessness. Their hope is revived when they discover that cutting-edge forensic genealogy may hold the key to finding Helene's murderer.

In the summer of 2003, the Iron Range of northern Minnesota is a peaceful community where parents let their kids play outside on their own without a second thought. But when five-year-old LeeAnna Warner vanishes without a trace, investigators do a deep dive into the quaint community and realize that some of the familiar faces in the neighborhood may be hiding some disturbing secrets that may never fully be uncovered.

In the '60s and '70s, a serial killer stalks young women in New Jersey; at the same time, three women in New York City are sadistically murdered; no one expects that one man is causing the mayhem, let alone a seemingly ordinary father of three.

When a vivacious young escort, Shannan Gilbert, vanishes on Long Island's south shore in 2010, her disappearance leads police to discover the bodies of ten other victims dumped by a serial killer.

Sherri Rasmussen and John Ruetten are enjoying newlywed life until one morning when Sherri calls into work sick. That night, John returns home to find his wife murdered. Years later, detectives discover Sherri's killer was too close for comfort.

Right before Thanksgiving, two masked gunmen reportedly invade a couple's home and kill the husband; with few leads, police use ballistics, forensics and neighborhood gossip to solve this cold-blooded murder.

When Ashley Ellerin is found murdered in her Hollywood bungalow, police zero in on the Hollywood heartthrob she was supposed to have a date with the night she was killed. The case takes a shocking turn as detectives realize Ashley is not the only victim, and discover they are on the hunt for a serial killer. The assailant's victim count grows until one woman manages to fight back so fiercely that he leaves behind critical blood evidence. But will they be able to finally catch him?

In the spring of 2001, former child actor and Baretta star Robert Blake just married Bonny Lee Bakely, the mother of his new baby girl. The couple are out to dinner in Los Angeles when Bakely is murdered in the passenger seat of the couple's car, execution style. Blake seems devastated, but as police investigate, they uncover a tale of a troubled marriage of convenience and a fight for custody that may have led to one of Hollywood's most infamous murders.

When a woman is found dead in her historic house on Horseshoe Lake, police chase her killer to the water where he drowns. But when the body is recovered, people are shocked to realize this story started 25 years earlier when two other family members were found murdered by the same man.

An unknown shooter unleashes carnage from Indianapolis to Wichita, Kansas, killing six in the spring of 1992 at various retail stores near 1-70, a major east-west highway that runs through the very heart of the Midwest. A sketch of the suspect is developed from various eyewitness accounts, but police are at a loss ... until one victim survives.

After moving to a new city following her parents' divorce, a 14-year-old girl finds herself lost and unloved within her new surroundings; she starts running away from home until one time, she never returns. It takes ten years before dark secrets are revealed.