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What really happened to a woman that slipped over the edge of a cliff is investigated.

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

Tension develops between two brothers who were arrested for the murders of four women. Also: an inmate discovers he has an incredible talent; two female inmates fight; and one of two friends suffers a tragedy.

The documentary series, which examines life at the Penitentiary of New Mexico, begins in Level 6, which houses the prison's worst offenders.

Recently uncovered pages from John Hinckley Jr.'s diary, which he began writing after he was arrested for trying to assassinate President Ronald Reagan, are revealed.

A rookie corrections officer at the Penitentiary of New Mexico deals with inmates in the lockup units of levels 5 and 6.

Detectives and forensic experts recount cold cases solved using familial DNA testing.

A 16-year-old girl who died in 1979 was last seen at a Dairy Queen in Las Vegas.

In 1981, Linda Slaten is sexually assaulted and murdered in her Florida apartment while her children sleep.

The three ways of leaving the Penitentiary of New Mexico---parole, death or escape---are explored. Included: rewarding inmates for good behavior by making them eligible for early release.

A stabbing is probed by the Investigative Services Unit.

A look at the reopened murder case of a young woman that police had considered to be closed.

Insights into the real story of the private royal, including a look at Diana's troubled marriage, her turbulent life in the royal family and the investigation into her death.

It started with a chance meeting at a nightclub and ended in murder. Those involved in the gruesome crime thought they had buried the secrets of the past, but a relentless team of investigators stopped at nothing to unearth the truth.

It takes 17 years to unravel the mystery surrounding the murders of three women in the middle of the Sonoran desert, and it's only solved when a fourth lady steps forward and tells the truth.

Real estate developer Gary Triano lived large. His murder was a bold statement. But not many people were talking. There were whispers of a mob connection, an angry investor or a mad ex and the mystery took nearly two decades to unravel.

Her life ended in mystery on a dead-end road: A mother of three who'd gone missing. For police, the investigation seemed to hit a dead-end, too. But a small-town story led to a very big break.

A young woman peers into her neighbor's yard and sees something for a few seconds. What she saw and what she did would set in motion a chain of events that would divide a family and a jury.

The stories of inmates whose sentences were extended due to infractions while incarcerated. Included: a car thief sentenced to 18 months who's now serving 16 years after committing aggravated battery on an officer on three separate occasions.

When a South Carolina coroner arrives at the scene of a car accident to find his friend deceased, he notices some unusual markings on her face and begins to think her death looks suspicious.

Rod Covlin calls 911 after his young daughter finds his estranged wife unconscious in the bathtub. Soon after her mysterious death, some loved ones would come to suspect that what happened was no accident.

The three ways of leaving the Penitentiary of New Mexico---parole, death or escape---are explored. Included: rewarding inmates for good behavior by making them eligible for early release.

A 22-year-old woman goes out for a jog in 1983 and never returned.

The identity of a woman who commited suicide in 1996 took decades before it was discovered.

The body of a little girl is found in the Arizona desert. Detectives are unable to identify her so the local community lays her to rest with the name "Little Miss Nobody".

A look at how inmates pass time in San Quentin State Prison. Included: an inmate who is creating a wall mural with brushes made from his hair and paint made from ink, shampoo and toothpaste; an inmate who cuts himself with his fingernails.

A look at one of the most important things in an inmate's life: visits from those on the outside. The meetings range from intimate visits with loved ones to business transactions to a way to smuggle drugs.

The discovery of a teenager's car abandoned on a New Jersey bridge turns into a homicide investigation. Police uncover a plot involving money, close friends and betrayal. Keith Morrison reports.

A Texas love triangle turns deadly, with a pink gun leading to an arrest. But new evidence forces investigators to reevaluate the case.

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.

Detectives in Washington D.C. discover a puzzling connection between two women who disappeared two decades apart; an investigation reveals a sinister secret hidden along one of the busiest stretches of interstate in the country.

Police believed a pair of double homicides in Nebraska, five years apart, might be connected. Investigators working to solve the crimes feared the killer might strike again.

A visit to Alcatraz in San Francisco Bay to examine the 1962 escape of three inmates and recall the legends of "the Rock" such as Al Capone and the Birdman of Alcatraz. Also: the search for a California couple who are suspects in an attempted-murder case.

A clumsy bank robber; an underground drug route between Mexico and the US; alleged paranormal events in a Texas subdivision.

A purportedly haunted ranch in Texas; an abandoned car and its missing driver; claims of corruption at a California prison. Also: a doctor raises suspicions.

A Wyoming amnesiac; two jailbreaks; a double homicide in Oklahoma. Also: a cyanide-laced potion kills five on St Croix.

An Oregon murder probe. Also: a hacker penetrates the CIA; a site of Old West gunfights is visited; bank robbers take hostages to execute their crimes.

A look at how inmates pass time in San Quentin State Prison. Included: an inmate who is creating a wall mural with brushes made from his hair and paint made from ink, shampoo and toothpaste; an inmate who cuts himself with his fingernails.

Arapahoe County, Colorado, 1983. The body of Sylvia Quayle is discovered by her distraught father in her Cherry Hills home.

DNA science finally identifies both killer and victim from a murder that took place back in Florida in 1991.

Tacoma, Washington State, 1986. 12-year-old Michella Welch goes missing in Puget Park.

An inmate who has served almost 20 years faces the prospect of release.

An annual poetry slam, which enables inmates to express themselves, is highlighted. Also: how inmates are classified based on the severity of their crimes and behavior.

When Cassy Farrington was found dead in her bathtub, her parents were determined to get answers, stopping at nothing until they found justice.

When a University of Utah athlete is found murdered on campus, investigators learn that she had reached out to the campus police for help multiple times before her death.

Big sky country and a difficult highway set the scene of a fatal car crash. Questions arise as to whether this was an accident or a crime and whether the secrets masking the truth are hiding in text messages sent just before a car crossed the line.

A brother seeks a long-lost sister. Also: the Boston Strangler; two dead teenage runaways; speculations on the development of military aircraft.

Arson begets a tragedy in Kansas City; four campers claim they were abducted by aliens; a woman leaves her apartment goes missing. Also: a fugitive's missing girlfriend.

A missing stripper; the murder of a Northwest Airlines employee; schemes by a man who assumed the names of soap-opera stars.

An allegedly cursed chair; a briefcase bomber; a home-contracting scheme. Also: a woman vanishes after telling her family about a trip she planned to take with her boyfriend.

A government intelligence officer vanishes; strange noises from the attic disturb a couple; a murder suspect disappears before he can be charged with the crime. Also: sleepwalkers.

Kenya Monge and Lydia Tillman didn't know each other but they would be forever related, both falling prey to a smooth-talking stranger with a terrifying secret.

Nikki Whitehead was a single mom working toward a brighter future. She found love, moved into a nice neighborhood, and enrolled in college. Then, tragedy struck. Police searched for answers but one thing was certain. This crime was personal.

Newsmagazine that delivers viewers stories ranging from mysteries to documentaries.

Young nursing student Michelle Le had disappeared. Something drew her out to her car, right before cameras caught the car peeling away. Next, there was a series of strange texts. It is discussed whether Michelle was missing or murdered.

An inmate who has served almost 20 years faces the prospect of release.

In 1984, the bruised and bloodied body of 25-year-old Naval recruit Pamela Cahanes is found in a lot.

San Diego 1969. 23-year-old Mary Scott is visited by a friend when she fails to show up for work.

Las Vegas, Nevada, June 1 1989. Stephanie Isaacson sets off on her morning walk to school; she never makes it.

The regrets of inmates are detailed via Scared Straight-type programs for teenagers and messages from prisoners recorded on personal video cameras.

Inmates' actions and their consequences.

A mother of two died after a minor fender bender, leaving loved ones confused and seeking answers.

A young woman was found almost dead in the middle of the road. There was little evidence to go on, so investigators needed to find out what happened from the victim herself, but the problem was that she could not remember.

Wealthy residents felt safe in their gated community, but it was not safe for one millionaire murdered in his waterfront home. Police investigated but the case grew cold. Turned out the key to solving it, or two keys, were right at the front door.

Included: a teenage amnesiac; evidence linked to the yeti; a marine's death.

Psychic David Morehouse; a casino owner's death. Also: a pilot vanishes during a flight; grisly remains are discovered by a homeowner while digging a swimming pool.

Boxer Sonny Liston's death; alleged UFO sightings over Belgium. Also: a car theft leads to murder.

A hostage scheme backfires; a wife vanishes during a vacation in Nevada; car accidents allegedly turn two people into psychics.

A California amnesiac. Also: a young camper vanishes in Canada; a stone etched with cryptic symbols is discovered.

Newsmagazine that delivers viewers stories ranging from mysteries to documentaries.

A wealthy doctor's wife was found dead on Valentine's Day. She had enemies, but he was a suspect regardless.

The murder of an art student from a small Texas town is investigated.

Investigators attempt to get to the bottom of a murder in an affluent, once-peaceful neighborhood.

The regrets of inmates are detailed via Scared Straight-type programs for teenagers and messages from prisoners recorded on personal video cameras.

Pensacola, Florida, New Year's Day 1985. The body of Tonya McKinley is found lying on the side of a city street.

Colorado Springs, Colorado, St. Patrick's Day 1987. The naked body of Darlene Krashoc is discovered by two patrol officers at 5.20am behind a restaurant.

A 17-year old girl arrives home in McCleary Washington and honks her car-horn. Her dad finds her distraught with duct tape around her mouth and her feet zip tied together.

How inmates treat first-timers and sex offenders.

Wedding preparations commence for a female inmate who's about to marry an alleged gang member, and an inmate is forced to choose between his crime family and his blood relatives in the series premiere of this look at life inside Suffolk County Correctional Facility in Riverhead, N.Y.

A husband is shot dead in his own bed. No one else in the house was hurt, not even his wife, who was sleeping beside him. Investigators were suspicious, but there were more surprises in store.

Steven B. Williams, a DJ with a golden voice, vanishes. The clue is wrapped in a napkin, tucked in a cabinet, hidden in a library.

A spotlight on a missing wife who was having an affair with a married guy.

A prolific bank robber is arrested; an embezzler vanishes; a stroke victim becomes an amnesiac. Also featured: the search for two teensagers who disappeared from a pyrotechnics display.

A wayward parolee harasses the FBI; a woman vanishes from a cruise ship; an alleged spontaneous human combustion; a psychic claims he can communicate with a dead sheriff.

An armoured-car robbery and a school bombing are featured. Also: A human skull is discovered beside a Mexican restaurant; a drug dealer is arrested.

A simian creature in Florida is examined; a man is arrested after murdering his whole family; evidence of reincarnation is explored; a suspected drug dealer becomes a fugitive.

A purported UFO sighting in Mexico City is explored; a suspect is charged with child molestation; two cases of abduction are probed; a body is discovered in the Chesapeake Bay.

A brother seeks a long-lost sister. Also: the Boston Strangler; two dead teenage runaways; speculations on the development of military aircraft.

Did Jennifer Corbin's desire to spend one last Christmas with her family lead to her murder?

After arguing with her new husband, Lisa Solomon leaves her home and vanishes into the cold night.

Could a killer's resentment of his family enjoying Thanksgiving together have lead to their murder?

Avis Banks is found dead in her garage. Police suspect that her fiance may not be all that he seems.

Toronto police are on the hunt for a serial killer who likes to dress up as Santa.