When Tina Sandoval disappears, her parents and loved ones spend years searching for her; a secret she was keeping may lead to clues about what happened to her.

The man convicted of murdering California entrepreneur Chris Smith speaks out.

Melissa Oxley wakes up to find her husband, Ben Oxley, has been shot in the head.

More than two decades after a woman is murdered in what appears to be a burglary gone wrong, a detective finds information that unlocks the mystery of what actually happened.

When a Pennsylvania man who was convinced his messy divorce put a target on his back is found stabbed to death, his friends and family realize he was right all along in predicting his own gruesome murder.

A California woman's two former husbands are mysteriously murdered, nearly 20 years apart.

A woman is found murdered after her close friend hears her screaming on the phone; the mysterious death of her boyfriend's twin brother leads investigators to a suspect.

Years after a Montana man is found dead, his son opens up a box of case files to find out what really happened.

The murder of a young businessman in Old San Juan, Puerto Rico, marks the start of a 15-year-long hunt to find the killer.

A double homicide in upstate New York leads detectives on a cross country investigation to piece together a case with a surprising suspect at the center. Dennis Murphy reports.

Nearly 10 years after Utah mother Susan Powell vanished, private journals, home videos and emails shed new light on what happened to her. Keith Morrison reports.

The murder of a woman sets off a chain of events, leaving one man dead, another man implicated and a diabolical scheme exposed.

Virginia Roberts Giuffre and other women share their accounts of sexual abuse by Jeffrey Epstein and others.

The search for MacKenzie Lueck, a college student who vanished from a park in Salt Lake City.

Interviews with people close to missing Connecticut mom Jennifer Dulos, including her estranged husband, who has since been arrested in connection with her disappearance.

Lester Holt spends two nights embedded inside the largest maximum security prison in America, the notorious Louisiana State Penitentiary, also known as Angola.

Recently uncovered pages from the diary of John Hinckley Jr, written after his arrest for the attempted assassination of President Ronald Reagan, are revealed. Troy Roberts reports.

Video of Robert Durst's friends testifying for the prosecution as to why he might have killed his best friend; a close friend of Durst's opens up about being called to testify against Durst after years of supporting him.

A wife calls 911 to report her husband has been shot on a country road in Texas. Could the dramatic police footage from the scene end up being key in the investigation? Josh Mankiewicz reports.

Pamela Smart was television's first true crime fascination after her husband was found murdered. Police discovered that Pamela Smart was keeping a big secret.

A San Diego woman arrives at an emergency room, near death. Doctors, the FBI and local law enforcement must solve not only a medical mystery, but also a horrific crime. Natalie Morales reports.

Cornell student and star athlete Charlie Tan excels in everything. But when he gets caught in the middle of a murder investigation, the community is left in shock.

A 59-year-old father is found dead in his home, they assume it's related to his ongoing health issues. But then, the coroner reveals he didn't die of natural causes. Keith

A mother has suspicions about the sudden death of her son in college, which was ruled an accidental overdose.

When a Kentucky man is convicted of murdering his co-worker, it appears the mystery is solved until a stunning disclosure years later turns the closed case upside-down. Josh Mankiewicz reports.

College senior Reagan Tokes was just months away from graduation when she was shot and killed in a public park. Her parents' heartbreak soon turned to outrage. Andrea Canning reports.

A missing mother in Florida leaves behind a three-year-old son, whose memory of their last night together offers some clues as to what happened to her. Dennis Murphy reports.

A successful business woman and mother of three is found shot in her office. Will justice be served? Keith Morrison reports.

Shirley Carter is gunned down in her kitchen in in rural Iowa. Dennis Murphy reports on the major developments in the case, and the family feud that led to a murder trial.

After a studious University of Utah athlete is found murdered on campus, it is revealed that she had reached out to the campus police for help multiple times before her death.

Two young women are shot and left for dead on a beach in Texas; a man is eventually convicted, but a stunning twist raises doubt.

The murder of a young schoolteacher in Pennsylvania goes unsolved for years, but investigators discover a new tool that may finally help unlock the murderer's identity.

The latest in the case of a missing young Oregon woman, whose disappearance led to an intense manhunt, after a suspect embarked on a two-state crime spree

The discovery of a 19-year-old's car abandoned on a bridge in New Jersey turns into a missing person case that evolves into a monthslong homicide investigation; police discover a plot involving money, close friends and a fatal betrayal.

When a dancer is murdered in her Virginia home, investigators are hopeful they can crack the case. But after interviewing a series of suspects, detectives realize the case is much more complicated than previously thought.

A Connecticut bank executive is targeted by a crew of criminals who invade his home, take him and his mother hostage and order him to rob his own bank. 

A mother in Pennsylvania disappears one afternoon after she is last seen by her co-workers leaving for lunch. The case remains cold even after 60 investigators try to crack it. Could the 61st detective finally have the answers? Josh Mankiewicz reports

An Alabama teen's father calls the police after he returns home to find his son had thrown a party, leaving the place trashed. Just 11 minutes after the deputy leaves their house, there is another 911 call placed.

When a young woman fails to show up to work, her mother rushes to her home to try to find her. What she discovers begins an investigation that leads to a suspect no one imagined.

Two young girls in Washington are snatched in broad daylight while riding their bikes. The case goes unsolved for decades, until a new detective with a local connection to the story tries to solve the mystery that haunted her childhood.

When Ohio mother Heather Bogle goes missing, a detective identifies multiple suspects, until he himself comes under scrutiny for his investigation. Josh Mankiewicz reports, and interviews Bogle's family, and four potential suspects in the early stages of the investigation, including her brother and ex-girlfriend.

A young woman finds out that her boyfriend might have shot and killed a college football player out of revenge. She struggles with coming forward to officials, fearing she could lose her life. Keith Morrison reports.

Key players in the case of Rod Covlin, a New York man found guilty of murdering his wife for her $5.3 million fortune and attempting to frame his then-teenage daughter, share their stories.

The case of Patrick Frazee, who is accused of murdering his fiancée Kelsey Berreth in November 2018, is examined. Included: remarks from Frazee's former girlfriend Vanessa Curie and her mother, Georgia.

Police are puzzled when a woman vanishes without a trace from inside her home in Washington, D.C. Adding to the mystery is that her security cameras don't show her leaving. As investigators begin to search for answers, they discover a connection to a decades-long disappearance of another woman.

The case of Mike Williams, who disappeared after duck hunting in North Florida on his sixth wedding anniversary, is examined.

NBC News' Dennis Murphy speaks to a Georgia father accused of murdering his ex-wife. While his friends come together to prove he is innocent, prosecutors count on his young children to testify against their own father.

Lead detectives and family members speak about the case of teenager Michelle Carter, who was convicted of bullying her then-boyfriend to kill himself.

A look at O.J. Simpson's infamous Bronco car chase and subsequent standoff with the LAPD SWAT team. Included: deposition tapes from Simpson's civil case; audio from a cell phone inside the Bronco; and remarks from then-LAPD homicide detective Tom Lange, then-LAPD commander David Gascon and then-SWAT sergeant Mike Albanese, as well as Nicole Brown Simpson's friend Kris Jenner, former prosecutor Marcia Clark, and photojournalist Roger Sandler, who was inside Simpson's estate.

A mother of two mysteriously vanishes from her parents' home in Michigan while going to check the mailbox, leaving her phone and identification behind. Police declare her dead before they even find her body. The disappearance and complicated investigation takes years for detectives to unravel.

An in-depth look at the history of allegations against singer R. Kelly, including interviews with several women who accuse Kelly of misconduct.

Kate Snow interviews an undercover agent who spearheaded the international manhunt for former journalist Amanda Lindhout's kidnapper.

The homicide of private first class soldier and young mother Karlyn Ramirez is investigated.

When a hard-charging boss in Arizona is shot to death, police uncover a complex web of bruised egos in his professional life and a trail of broken hearts in his personal life. Josh Mankiewicz reports.