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

In 1981, a woman and three teenagers are murdered in a cabin in the remote town of Keddie, Calif., and no one is ever brought to justice; now, new evidence may hold the key to finally cracking this case.

In 1980, Tim Hack and Kelly Drew go missing from a small Wisconsin town, then their bodies are found in a field; a woman comes forward nearly 40 years later to help solve the so-called "Sweetheart Murders" of Hack and Drew.

In Philadelphia, police make a horrific discovery 18 months after a woman goes missing; the police pursue the woman's killer, but he always manages to stay one step ahead of the law.

A premiere fishing boat explodes into flames just off shore, stunning the small fishing town of Craig, Alaska; after fighting the flames, state troopers discover the remains of a young family and few clues as to could have set the ship blaze.

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.

So-Cal surfer and tech entrepreneur Chris Smith dreams of making a tidy sum of money and surfing off into the sunset; it seems as though his dreams have come true, but all is not as it appears.

In 2011, a 10-month-old baby girl goes missing from her home in Kansas City, Mo., and her family fears she's been kidnapped by a drifter, only to be accused by the police of being responsible for her disappearance.

On June 6, 1992, Suzie Streeter and Stacy McCall attend parties celebrating their high school graduation; by morning, the teenagers have gone missing, along with Suzie's mother, Sherrill Levitt; the case leads police on a nationwide search.

NBA basketball player Lorenzen Wright goes missing outside of Memphis, Tenn., then his body is discovered in the woods, and investigators find out this case is far from a slam dunk.

A brutal 1970 home invasion claims the lives of Army surgeon Jeffrey MacDonald's wife and daughters, leaving him the lone survivor; authorities doubt his story of murderous hippies and believe MacDonald committed the crime himself.

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.

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.

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.

When an 11-year-old Arizona girl vanishes while waiting for an ice cream truck, it's clear she's been abducted; the search for her leads to a trail of suspects, making it the largest missing child investigation in Arizona history.

The morning of his anniversary, Mike Williams goes duck hunting; when he fails to return home, an all-out search commences, but it's only the beginning of a sordid mystery that will take close to 20 years to solve.

In the summer of 1980, a popular teen goes for a run around her hometown in Maine and, days later, her savagely beaten body is found; what happened remains a mystery for years until her mother intervenes and forces police to re-examine the case.

In the summer of 2000, bags full of body parts start appearing all over the San Francisco Bay Area; investigators follow the trail of grisly clues to a secret cult carrying out a sinister scheme.

In 1992, a 19-year-old woman is brutally assaulted outside of Desert Hot Springs, Calif.; miraculously, she escapes but lives in constant fear that her assailant will find her again one day, not realizing she has survived a serial killer.

In the early 1970s, Washington D.C. is terrorized by a cunning killer who abducts and murders six young African American girls; police and the community are outraged by the serial killings that target young children in their own neighborhoods.

In Grand Prairie, Texas, a game of truth-or-dare leads to a startling confession in the 1995 shooting death of 16-year-old Adrianne Jones.

From the moment a homicide is reported, a file is assembled to document every facet of the investigation -- crime scene photos, notes and observations, forensic reports, witness interviews, suspect profiles -- and continues to grow with new information until an arrest is made and conviction attained. Investigation Discovery opens these "murder books" to tell haunting tales buried within the pages. Hourlong episodes take viewers back in time with details of decades-old cold cases using actual archival footage, crime-scene evidence and first-person interviews with lead investigators, unraveling the mystery and uncovering what broke the cases open.

"Betrayed" reveals chilling stories of chasing the American dream and how the veneer can dramatically crumble, ending in murder at the hands of a trusted family member, co-worker, lover, or friend. The cases of deception are told through the lens of the fictionalized, first-person perspectives of the victims. As investigators, family, and friends peel back the layers and facts of each case, the otherworldly narrator already knows where the trail ends. The narrator guides viewers through various relationships, raising suspicions about who will commit the ultimate betrayal.

Investigation Discovery joins forces with reporters from People magazine to tell stories of high-end fashion icons and their couture crimes that captured headlines. The adage"if looks could kill" takes on entirely unique meaning in the series, which grants People's journalists exclusive access beyond the catwalk to reveal that fashion can sometimes be fatal. The hourlong tales of depravity, obsession, and family betrayal in the fashion world all have a common thread -- cold-blooded murder.

Anchored by Lester Holt, "Dateline" is NBC's signature newsmagazine, bringing viewers storytelling at its best by putting the pieces together to present the full picture of real-life events. NBC News correspondents cover compelling stories and issues of the day, ranging from mystery and crime to in-depth investigations and breaking-news events.

"Dateline" has been a staple of the newsmagazine genre since premiering in 1992. Given how long it's been on the air, the show has an extensive archive of in-depth news stories and investigative journalism. This syndicated version offers viewers another chance to watch some of the show's previous content, serving up real-life mysteries and in-depth investigations from the show's 20-plus years on the air. Cases involving murders and missing people are frequent topics on the series that has won multiple Emmys in the news and documentary category.

A version of the award-winning CBS true-crime series delves into investigations of murder, gambling, missing persons and other incidents, with "48 Hours" correspondent Maureen Maher introducing reports.

Veteran journalist María Elena Salinas has made a name for herself in the Spanish-speaking community as a longtime news anchor on Univision. In this series, she goes from reporting the news to investigating it as she goes beyond the headlines to uncover the truth about headline-making crimes. Salinas attempts to remove the clutter that surrounds cases that were in the media spotlight and find information that the media originally missed when reporting on the stories as they were happening. In her searches, Salinas finds new evidence, gets previously unheard perspectives and provides updates to the cases.

"Accident, Murder, or Suicide" investigates the deaths that are just a little bit too mysterious. It explores the unbelievable true stories in this hourlong program. Each episode retraces the investigation from the start to the end. Investigators take viewers through the twists, turns, and unexpected surprises as they dissect the red flags, show evidence, and point out the strange behavior that puts everything into question.