The body of newlywed Rey Rivera was found in an abandoned conference room at Baltimore’s historic Belvedere Hotel in May 2006, eight days after he mysteriously disappeared. While the Baltimore Police maintained that the 32-year-old committed suicide by jumping from the hotel’s roof, the medical examiner declared Rey’s death “unexplained.” Many, including his devastated wife, Allison, suspect foul play.

Patrice Endres, 38, mysteriously vanished from her Cumming, Georgia, hair salon in broad daylight, during a 13-minute timeframe, leaving behind her teenage son, Pistol. Patrice’s disappearance intensified the existing tensions between Pistol and his stepfather as they dealt with the loss and searched for answers.

In April 2011, French police discovered the wife and four children of Count Xavier Dupont de Ligonnès buried under the back porch of their home in Nantes. Xavier, the family patriarch, was not among the dead and nowhere to be found. Investigators gradually pieced together clues and a timeline that pointed to Xavier as a devious, pre-meditate killer. For instance, they now know that shortly before the crimes occurred, Xavier inherited a gun that was the same model as the murder weapon.

Alonzo Brooks, 23, never returned home from a party he attended with friends in the predominantly white town of La Cygne, Kansas. A month later, a search party led by his family locates Alonzo’s body — in an area that law enforcement had already canvassed multiple times.

On September 1, 1969, many residents in Berkshire County, Massachusetts were traumatized by a sighting of a UFO. Eyewitnesses — many just children at the time — have spent their lives trying to convince the world that what they saw was real.

At age 17, a guilt-ridden Lena Chapin confessed to helping her mother dispose of her murdered stepfather’s body four years prior. In 2012, Lena was issued a subpoena to testify against her mother in court, but the authorities were never able to deliver the summons — because Lena had disappeared, leaving behind a young son.

Police find the body of former White House aide Jack Wheeler in a landfill. Security footage captures strange events in the days leading up to his death.

After checking in at a luxury hotel with no ID or credit card, a woman dies from a gunshot. Years later, her identity — and her death — remain a mystery.

Given a furlough to go Christmas shopping in 1973, a convicted killer escapes. Police have come close to apprehending him but believe he's still at large.

A massive earthquake and tsunami devastated Japan in March 2011. Residents share stories of the spirits they encountered in the wake of the disaster.

On an icy night, police find JoAnn Romain's abandoned car and assume she drowned in a nearby lake by suicide. But her family suspects foul play.

In May and August 1989, two toddlers vanished from the same New York City park. A search turned up nothing — but their families haven't given up hope.