A man's children stand by him as he deals with courts in upstate New York; a woman accused to attempting to hire a hit man to kill her husband.

The investigation into the death of a woman whose remains were found in her Frisco, Texas, garage leads detectives to a series of suspects with connections to the victim's complicated and secretive life.

The investigation into the disappearance of a Marine's 19-year-old wife reveals a secret love triangle and multiple suspects.

After a man's conviction for murdering his wife is overturned, new allegations take the tale in an unexpected direction.

A son enlists the help of his attorney father after he watches a "Dateline NBC" report on the murder of Michelle O'Keefe. They soon discover disturbing questions. Keith Morrison reports.

Police initially suspect natural causes as they investigate a man's death, until they learn about an unconventional love triangle, which points the investigation in a new direction.

A Jacksonville, Fla., firefighter discovers a disturbingly violent scene in his darkened bedroom on a Halloween weekend.

A son uncovers a dark family conspiracy when he questions his mother following a man's apparent suicide.

The investigation into the death of Spokane, Wash., businessman exposes a web of malevolence extending from the Pacific Northwest to a North Dakota oil field.

A daughter's determination to learn more about her mother's mysterious death leads to the re-opening of a 30-year-old cold case.

A man who was recently acquitted of the murder of his ex-girlfriend's 12-year-old son tells his story; interview with the victim's mother and key players in the case.

A man convicted of murdering a woman in her upscale Austin, Texas, home tells his story for the first time.

The investigation into the death of an entrepreneur reveals secrets he had been hiding and a list of people who might want him dead.

People involved in the investigation of the 1996 murder of 6-year-old JonBenét Ramsey discuss the case; case documents made public for the first time; footage of the police interview with JonBenét's brother.

Montana, 1999: Kathryn Laird, the wife of an attorney, is found drowned. A strong swimmer, Kathryn's family immediately doubts the apparent suicide.

Radio host Robert F. Kennedy Jr. talks about the 1975 murder of Martha Moxley, for which his cousin, Michael Skakel, served 11 years in prison before his conviction was vacated.

A look at the crimes committed by Charles Manson and his followers in 1969, including archival footage and interviews with those close to the events.

Special Dateline on Assignment: Gunman attacks bar in Orlando Fla, Killing 50 and injuring at least 50 more

Even in a peaceful place, like just south of Glacier National Park in Montana, tempers can flare and personalities will clash. One man shoots, another dies…but the story can't be that cut and dry, can it?

When a young woman is found dead inside her Jacksonville Beach apartment, police hope they'll quickly find her killer. Instead, it takes more than a year to find a microscopic clue and a huge stroke of luck to solve their case.

When a young, handsome veterinarian is found dead in his home in Montana, the mystery remains unsolved for nearly two decades.

Police in a small Texas town believe a man may be behind the shooting deaths of his wife and her son in their home.

The notorious hacker, Marcel Lehel Lazar (also known as "Guccifer"), who discovered Hillary Clinton's private email account; giant chimpanzees threatened by poachers; new insight into recovery from traumatic brain injuries.

A teenage girl is murdered at a scenic spot on a Utah river. The case almost goes cold until a hairdresser turned detective, with the help of the victim's determined mom, finds the truth.

Dark secrets come to light as officials investigate what happened to a wife and mother of three who was found dead in her bathtub.

The life and legacy of legendary songwriter, producer, singer and musician Prince; music legends who have recently passed.

The vanishing of a female Realtor from Little Rock, Ark., leads detectives on a desperate chase.

In small-town Colorado, a sudden marriage sows tension in two families. Then a murder uncovers secrets, lies, and a mystery that had been buried for years.

"What happened one cold January night in the wee hours was especially alarming..." Dennis Murphy reports on a house fire that breaks out in the middle of the night in Kentucky. When Julie Griffith is found dead amongst the rubble, investigators soon discover the fire was anything but an accident.

After a Idaho woman falls in love with her married boss, the affair leads to a violent confrontation. Keith Morrison reports.

Dennis Murphy reports on the case of a 26 year-old model and aspiring Playboy Playmate who goes missing after visiting a Miami nightclub with her boyfriend. Within 24 hours of her disappearance, police find her brutally murdered.

After a woman reports a prowler, police find her Olympic bronze medalist husband dead in their backyard.

Daughters Alexis and Rachel share fond memories of their mother with Keith Morrison.

Keith Morrison reports on a Chicago woman from a large family missing for several days. As the whole city joins in the search, detectives begin to suspect that a man in her life has many secrets.

The discovery of an Army captain's death in her El Paso, Texas, home shakes her tight-knit military community.

Prosecutor Marcia Clark reveals details about the trial of O.J. Simpson; interviews include Kris Jenner, Denise Brown, Fred Goldman, Kim Goldman, Kato Kaelin, Skip Junis, and Bob Costas.

An investigation into the murder of a beloved couple in South Carolina reveals a feud and divides a family.

Police investigate the disappearance of a woman from a small Michigan town.

Rocky Mountain National Park rangers question whether a woman's fatal fall was an accident or the result of an act of violence.

Detectives suspect an inside job when a coin collector and his wife are found dead in their home with no sign of forced entry or evidence of theft.

The drug-related death of a 17-year-old girl sheds light on a new class of synthetic drugs that has law enforcement agencies on alert.

The mystery of a Florida hotel owner's disappearance confounds family, friends and the detectives investigating the case.

Robert Davis, who was convicted of murdering a woman and her son, claims his confession was coerced and tries to prove he is innocent.

As detectives struggle to find leads in the murder of a college student, the perpetrator strikes again.

Years after a 16-year-old boy confessed to a double murder and was sentenced to life in prison, a local businessman tries to prove the confession was coerced and the teen was wrongfully convicted.

The investigation into the death of a Florida firefighter reveals a tale of secrets, lies and infidelity.

The latest updates on Ryan Ferguson, who spent nearly 10 years in prison for a murder he did not commit.

The controversial conviction of Steven Avery -- who was previously exonerated after spending 18 years in prison for a sexual assault he did not commit -- in the murder case of Teresa Halbach.

Now exonerated, Eric Glisson discusses the 18 years he spent in prison for a murder he did not commit.

The 2015 retrial of Russell Faria, who was convicted years earlier for murdering his wife, reveals surprising new allegations.

Stories from the people who were egregiously harmed by the actions of Michigan oncologist Farid Fata, who pleaded guilty to fraud, conspiracy and money laundering; how Fata's lies were exposed.

Stacy and Jason Bingham discuss their five children's health issues as one child undergoes a second heart transplant and another's child's heart begins to fail.

Rachel Buffett, whose former fiance, Daniel Wozniak, was convicted of two grisly murders, talks about being at the center of the investigation.

When a young, handsome veterinarian is found dead in his home in Montana, the mystery remains unsolved for nearly two decades.