Keith Morrison reports on a love triangle that led to years of stalking, destruction of property, threats and murder.

A mother of four dies unexpectedly on Valentine’s Day. Everyone in town assumes she died of natural causes until a detective suspects someone has gotten away with murder. Dennis Murphy reports.

When a model and up and coming YouTube celebrity is found dead, police question her husband to see if he can provide any answers. Keith Morrison reports on what could have led to her death.

When Crystal Taylor was murdered, her sisters were determined to find the killer. Josh Mankiewicz reports on the unexpected source that turned the case upside down.

After a young woman goes missing from a Halloween party, a town turns out to search while detectives settle in for a long investigation. Keith Morrison reports.

When a young father is murdered at work, the investigation uncovers deep secrets about sex, religion, friendship, and family. Josh Mankiewicz reports.

Rachel Jeffs talks about what it was like growing up as the daughter of Warren Jeffs, the self-proclaimed prophet of the FLDS.

Keith Morrison reports on a murder in Fort Worth, TX.

The Menendez brothers were convicted more than two decades ago of murdering their parents in Beverly Hills. Keith Morrison reports.

The unexplained death of a beloved chiropractor becomes a criminal investigation when authorities discover she’d been poisoned. Andrea Canning reports.

After a small business owner and his bride are murdered just a few months after their wedding, police start looking into stories about a nasty family feud. Josh Mankiewicz reports.

Brandy Daniels believed someone was stalking her. Then, the single mother was found slumped over in her car, shot dead. Investigators would spend years navigating the twists and turns searching for her killer.

Keith Morrison reports on conman John Meehan, who made national headlines last year after his crimes and their final, deadly culmination were featured in the popular podcast, ‘Dirty John.’

A former Marine, who once was the hero for a woman in an abusive marriage, is back on "Dateline." Included: whether his desire to help has gone to far.

A couple’s anniversary celebration ends in murder, in what appears to be a home invasion. Yet, investigators think the suspect might be much closer to the victim. Dennis Murphy reports.

Brandy Daniels believed someone was stalking her. Then, the single mother was found slumped over in her car, shot dead. Investigators would spend years navigating the twists and turns searching for her killer.

A murder outside Pleasantville, Iowa divides a family and forces one man to take the investigation into his own hands. Dennis Murphy reports.

A young mother disappears after leaving her newborn with her pastor and his wife. Florida detectives search for her, but instead uncover a web of secrets and lies. Keith Morrison reports.

When thousands gather at the 2011 Indiana State Fair for a concert, tragedy strikes. Concert goers put themselves in harm’s way to try and save complete strangers. Andrea Canning reports.

A young Army medic based at Ft. Bragg, North Carolina goes missing. Police have a suspect, but can’t solve the case, until an unorthodox private investigator steps in. Andrea Canning reports.

A former marine, who once was the hero for a woman in an abusive marriage, is back on ‘Dateline.’ But this time, has his desire to help gone too far? Andrea Canning reports.

When a woman is found dead in her home, it's ruled a suicide. But when a new investigation begins, police question if this is a murder case. Will the truth be revealed? Keith Morrison reports.

A complicated Texas love triangle ends in murder. A pink gun leads to an arrest, until new evidence prompts investigators to rethink the case. Josh Mankiewicz reports.

The idyllic town of Montecito was threatened by the worst wildfire in California history, then inundated by catastrophic mudslides. Keith Morrison reports on four families who barely escaped alive, and the rescuers who risked their own lives to help

A bizarre cyber-revenge case lands a young woman in jail and makes national headlines. Dennis Murphy reports on the unexpected twist that revealed the real culprit and the new developments in the case. Andrea Canning reports on a murdered Tennessee woman whose case stumps investigators.

In a hard-to-believe case, a violent stalker attempts to arrange the death of his ex-girlfriend. He even convinces his new girlfriend that her divorced husband should be added to the list.

The disappearance of a young woman from Bend, Oregon leads to an intense manhunt after the suspect sets off on a two state crime spree. Keith Morrison reports.

When one woman breaks off her relationship with a boyfriend she says abused and stalked her, he goes on to something even worse. His accused accomplice? His new girlfriend. Andrea Canning reports.

After a 15-year-old girl disappears, investigators discover a creek where the local teenagers hang out. Could the secret spot hold the answer to her disappearance? Dennis Murphy reports.

Rapper Meek Mill interview; exploring controversies surrounding the criminal justice system, including the parole system, wrongful convictions, challenges faced by law enforcement, alleged police abuse and more

When a young woman is found dead in a field on the outskirts of Green Bay, Wisconsin, detectives uncover a Fitbit that helps them solve the mystery. Andrea Canning reports.

In a suburb of Toronto, a family lives in fear as one relative after another is found dead over the years in the same home. Andrea Canning reports.

Two young people from opposite sides of the world find themselves falling in love on the eve of one of the biggest natural disasters in recent memory. Keith Morrison reports.

NBC News’ Kate Snow sits down for an exclusive in-depth interview with Andrea Constand, the first woman to pursue charges against Bill Cosby that ultimately led to his conviction.

Andrea Canning reports on cases of alleged hazing at schools and fraternities across the country, including LSU, Texas Tech, Florida A&M, Rider University and more.

It was a perfect apartment. But what happened in there one night? Keith Morrison has the details on an all-new Dateline Friday 10/9c.

Keith Morrison follows a cold case for nearly 10 years, as a father fights to bring his daughter’s killer to justice through one setback after another.

A woman from Washington State takes a DNA test to learn more about her family history. A remarkable discovery changes her family forever. Harry Smith reports.

When a prominent attorney claims to have accidentally shot his wealthy wife, the local prosecutor questions his story. Was it an act of murder? Josh Mankiewicz reports.

Jacob Soboroff reports on the reality of life along the U.S.-Mexico border.

Josh Mankiewicz reports on the race against time to make a connection between several separate murders in the Phoenix, Arizona area -- before the killer strikes again.

A mother is murdered in her home and police suspect her husband is the killer. It takes 14 years before he’s caught and convicted. But it’s feared he could kill again. Keith Morrison reports.

Josh Mankiewicz reports on the Jonestown massacre, the largest mass murder-suicide in modern history

A Knoxville, TN community is shaken when a popular high school student is found murdered in her bed. Two students who helped police solve the case speak to Andrea Canning.

When two mothers meet after one of their sons disappears after a college party, their search for answers leads them down an unexpected path. Dennis Murphy reports.

When a beloved former firefighter is found dead in his garage, police are desperate for answers. Dennis Murphy reports.

Actress Catherine Oxenberg shares how she tried to save her daughter India, who Catherine says was brainwashed by the controversial self-help group NXIVM for several years. Megyn Kelly reports.

A murder case considered closed by North Dakota detectives is suddenly reopened when a confidential informant comes forward with a tip about an unlikely suspect. Keith Morrison reports.

In-depth look at the growing homeless epidemic affecting half a million Americans, including an eye-opening tour of L.A.’s Skid Row, the nation’s epicenter of homelessness. Craig Melvin reports.

A high school girl, nearly beaten to death in her own home, goes under hypnosis in an attempt to identify her attacker. Andrea Canning reports.

When a soldier who just returned from Afghanistan is gunned down on the side of the road in Kentucky; detectives quickly uncover a secret that could solve the case.

Keith Morrison reports on a notorious serial killer, nicknamed Hannibal, who murdered several people while working as a confidential informant for the FBI.