This is the shocking and gruesome mystery of John Wayne Gacy, a popular Chicago businessman and part-time clown who was leading a double life in the 1970s. By day he was a community leader and by night a predator of young men.

In Chicago, community leader and part-time clown John Wayne Gacy leads a double life, transforming into a monster who preys on male teenagers and becomes the most prolific serial killer of his day.

The Zodiac Killer terrorizes Northern California in the late 1960s; he taunts the public with cryptic clues, threats of violence and ciphers that are supposed to lead to his identity, but mostly go nowhere.

The Zodiac Killer terrorizes Northern California in the late 1960s; he taunts the public with cryptic clues, threats of violence and ciphers that are supposed to lead to his identity, but mostly go nowhere.

More than 900 Americans died in an isolated jungle in northern Guyana in November 1978; Jim Jones has gone down in history as a madman who drove his followers to suicide, but the truth is more complicated and tragic than that.

He is among the most infamous serial killers in American history. From 1976 to 1977, David Berkowitz terrorized New York City – under his creepy self-given moniker: the Son of Sam. Using a large caliber. 44 revolver, he unleashed eight horrific shootings across three different boroughs- wounding seven people and killing six. Despite an extraordinary investigation, and hundreds of NYPD officers working the case– Berkowitz’s crime spree lasted over a year. How did he get away with it? What clues did investigators miss? The detectives who worked the case tell the true tale of what it was like in New York City with a gun-toting murderer on the loose.

In January 1974, four members of a family are brutally tortured and murdered in Wichita, Kansas. The murders shock the safe midwestern city, but little do they know, it is just the beginning. He calls himself “B.T.K.” which stands for Bind, Torture, Kill and for decades this bloodthirsty serial killer terrifies Wichita as he murders again and again and again. Wichita residents live in fear that they will be his next victim. Who is B.T.K. and will police capture this crazed killer before he strikes again?

B.T.K. stands for Bind, Torture, Kill., the name the serial killer gave himself. After terrorizing Wichita, Kansas with multiple killings from 1974-1991 he goes quiet. But he resurfaces in 2004 and residents of the midwestern city are once again petrified. For months he plays a cat and mouse game with law enforcement and the media taunting them as he seeks the attention he craves. But then… he makes a mistake. And when “BTK” is finally apprehended it is chilling to discover that he has been hiding in plain sight for years.

The summer of 1985 was one of the hottest Los Angeles had seen in a century. But terrified residents weren’t sleeping with the windows open, they weren’t sleeping at all. A killer was on the loose. And though the 1980s were considered the decade of the serial killer – one man stood out. He was the Night Stalker – his crimes were random, vicious and committed in the name of Satan. His victims ranged from toddlers to the elderly. And as the city was paralyzed with fear, he went unchecked while police struggled to stop him. Then the L.A.P.D. get a tip, a teenage boy spotted a suspicious car leaving a crime scene. Would it be enough to bring the Night Stalker to justice?

Through the record-breaking heat of the spring and summer of 1985 in California, a savage killer was on the loose. The Night Stalker had been linked to at least 15 murders from children to the elderly, male and female, wealthy and poor. Then police get a break – a tip from a teenage boy leads to the identity of the Night Stalker. Twenty-four hours later a mob of angry citizens track him down and capture him. But the man who terrified the nation for more than a year isn’t finished yet. His trial is a new, bizarre chapter that has some wondering if the Night Stalker will escape justice.

n April 1973, 24-year-old Edmund Kemper had murdered 6 coeds in and around the city of Santa Cruz, California, shaking the community to its core. But Kemper reached a breaking point, and what the public would soon learn, was almost impossible to believe. Told through interview footage with Kemper himself, as well as people who were there, this episode takes viewers inside the mind of a serial killer, from a childhood wrought with abuse through an early life of violence. Kemper outlines his motives for the killing spree and describes the terrifying methods he used to slaughter young women, operating right under everyone’s noses. As Kemper explains in great detail, he spared no one from his madness, not even his own flesh and blood. With his willingness to tell his story so openly, Kemper would go on, years later, to assist the FBI in profiling serial killers, offering insight into how, and why, killers like himself commit such horrific acts.

The Golden State Killer invaded homes, tortured and terrorized families, committed fifty brutal rapes and thirteen vicious murders, and was on the loose for forty-four years. Cold case Investigators chased down thousands of leads without ever getting their man. But a new forensic tool breaks the case and exposes this remorseless predator – Joseph DeAngelo – his family, his background, and his life story; and finally, scores of victims get a measure of long-awaited justice.

he Golden State Killer invaded homes, tortured and terrorized families, committed fifty brutal rapes and thirteen vicious murders, and was on the loose for forty-four years. Cold case Investigators chased down thousands of leads without ever getting their man. But a new forensic tool breaks the case and exposes this remorseless predator – Joseph DeAngelo – his family, his background, and his life story; and finally, scores of victims get a measure of long-awaited justice.

In November 1974, six members of the DeFeo family were found murdered inside their beautiful seaside home. The mother, father, and four of their children were shot in the back as they lay sleeping in their beds. The bodies were discovered by the only family member left alive – the oldest son Butch DeFeo. What really happened that night in Amityville? Who murdered the DeFeo family and why? What caused the strange events in the house near the sea? Parapsychologists and psychics descend on the house to investigate claims of levitating objects and demonic possession in an attempt to explain why, 50 years later, this house is still a source of nightmares.

In November 1974, six members of the DeFeo family were found murdered inside their beautiful seaside home. The mother, father, and four of their children were shot in the back as they lay sleeping in their beds. The bodies were discovered by the only family member left alive – the oldest son Butch DeFeo. What really happened that night in Amityville? Who murdered the DeFeo family and why? What caused the strange events in the house near the sea? Parapsychologists and psychics descend on the house to investigate claims of levitating objects and demonic possession in an attempt to explain why, 50 years later, this house is still a source of nightmares.

In 1968, an 8-year-old girl is abducted and raped. The Los Angeles police were just moments from catching her attacker, but he eludes them and escapes to New York where he kills a young woman. This is the beginning of a monstrous killing spree of young girls and women. When police discover who is behind these horrific murders, they are shocked to find it's a handsome, charming photographer. With a string of murders already behind him, incredibly, Rodney Alcala is chosen to appear on the national game show, "The Dating Game." What happens next makes Rodney Alcala one of the most horrific serial killers in US history.

In 1968, an 8-year-old girl is abducted and raped. The Los Angeles police were just moments from catching her attacker, but he eludes them and escapes to New York where he kills a young woman. This is the beginning of a monstrous killing spree of young girls and women. When police discover who is behind these horrific murders, they are shocked to find it's a handsome, charming photographer. With a string of murders already behind him, incredibly, Rodney Alcala is chosen to appear on the national game show, "The Dating Game." What happens next makes Rodney Alcala one of the most horrific serial killers in US history.

He was a family man, living in a New Jersey suburb with his wife and three kids. But unbeknownst to his neighbors, Richard Kuklinski held a dark secret: he was the "Iceman" – a cold-blooded killer who was part-time mob hitman for hire, and full-time psychopath. This intimidating, oversized killer managed to evade the police with ease for years. That is, until a few smart investigators started connecting the dots between seemingly unrelated murders and a mystery man known as "Big Rich."

He was a family man, living in a New Jersey suburb with his wife and three kids. But unbeknownst to his neighbors, Richard Kuklinski held a dark secret: he was the "Iceman" – a cold-blooded killer who was part-time mob hitman for hire, and full-time psychopath. This intimidating, oversized killer managed to evade the police with ease for years. That is, until a few smart investigators started connecting the dots between seemingly unrelated murders and a mystery man known as "Big Rich."

From 1987 to 1992, young women were abducted and murdered north of the U.S.-Canadian border. A tip led cops to an unlikely suspect: a blond, blue-eyed accountant who lived with his wife in a pink house in the suburbs.

From 1987 to 1992, young women were abducted and murdered north of the U.S.-Canadian border. A tip led cops to an unlikely suspect: a blond, blue-eyed accountant who lived with his wife in a pink house in the suburbs.

When college-aged women go missing, the investigation leads authorities to a local star athlete.

When college-aged women go missing, the investigation leads authorities to a local star athlete.

In the fall of 1977, bodies of young women begin piling up in LA. Almost all of the victims are nude, discarded on hillsides showing signs of torture. It is nearly a year before two murders 1200 miles away uncover the Hillside Stranglers.

Samantha Koenig was closing shop in Anchorage, Alaska, when a man known in the community as a business owner and caring father, approaches. After kidnapping Samantha, an intense manhunt took authorities on a cross country investigation.