On February 13, 2017, two Indiana teenagers, Abigail Williams, 13, and Liberty German, 14, went for a walk in the woods near the abandoned Monon High Bridge. They never returned home.

In 1911 two British heiresses, Claire and Dora Williamson, read a brochure about a revolutionary fasting treatment that promised a lifetime of good health. The sanatorium in the village of Olalla, west of Seattle, was surrounded by a beautiful forest, sparkling waters and fresh air. The sisters agreed it sounded perfect and exactly the restorative holiday they needed. But within a month of arriving, under the supervision of Doctor Linda Burfield Hazzard, Claire and Dora began to realise the frightening truth – they were not patients but prisoners at the isolated sanitorium.

On a chilly November afternoon in 1998, a tearful 36-year-old man walked into the Humboldt County Sheriff's Department in Eureka, California, and confessed to something horrible. "I hurt some people," he said. Inside his pocket was the ghastly proof of his statement. But there was more to Wayne Adam Ford than the trail of mangled victims he left behind. More, even, than the twisted predator inside, which drove him to increasingly perverse sexual appetites.

The call came on the morning of July 13, 2011, from the historic Spreckels Mansion, a lavish beachfront property in Coronado, California, owned by pharmaceutical tycoon and multimillionaire Jonah Shacknai. When authorities arrived, they found the naked body of Jonah's girlfriend, Rebecca Zahau, gagged, her ankles tied and her wrists bound behind her. Jonah's brother, Adam, claimed to have found Rebecca hanging by a rope from the second-floor balcony. On a bedroom door in black paint were the cryptic words: She Saved Him Can You Save Her.

Jenn Corbin appeared to have it all: two dear little boys, a posh home in one of the upscale suburbs of Atlanta, expensive cars, a plush houseboat, and a husband - Dr. Bart Corbin, a successful dentist - who was tall, handsome, and brilliant. But gradually, their seemingly idyllic life together began to crumble. Bart was distraught and Jenn seemed disenchanted. Then, just a few weeks before Christmas 2004, Jenn was found dead with a bullet in her head, an apparent suicide....

On May 31, 2014, in the Milwaukee suburb of Waukesha, Wisconsin, two 12-year-old girls attempted to stab their classmate to death. Morgan Geyser and Anissa Weier’s violence was extreme, but what seemed even more frightening was that they committed their crime under the influence of a figure born by the internet: the so-called “Slenderman”. Yet the even more urgent aspect of the story, that the children involved suffered from undiagnosed mental illnesses, often went overlooked in coverage of the case.

David Brown was the consummate entrepreneur: a computer wizard and millionaire by age thirty-two. When his beautiful young wife was shot to death as she slept, Brown's fourteen-year-old daughter, Cinnamon, confessed to killing her stepmother. The California courts sentenced her harshly: twenty-four years to life. But in the wake of Cinnamon's murder conviction, thanks in part to two determined lawmen, the twisted private world of David Brown himself unfolded with astonishing clarity—revealing a trail of perverse love, twisted secrets, and evil mind games.

On September 28, 2000, former Indiana state trooper David Camm made a frantic call to his former colleagues in the state troopers office: He had just walked into his garage and found lying on the floor the bodies of his 35-year-old wife Kim and their two children Brad and Jill, ages seven and five. Three days later, things got worse when police arrested David Camm for the triple murder. Soon new stories started emerging about mistresses and violent bursts of temper.

Although happily ensconced in a loving second marriage and a new family of quadruplets, Sheila Blackthorne Bellush never truly escaped the enslavement of her ex-husband, multimillionaire Allen Blackthorne, a handsome charmer - and a violent, controlling sociopath who terrorized her for a decade after their divorce. When Sheila was slain in her home, in the presence of her four toddlers, authorities raced to link the crime to Blackthorne, the man who vowed to monitor Sheila's every move in his obsessive quest for power and revenge.

Sharon Marshall was a brilliant and beautiful student whose future was filled with promise—until her murderous, fugitive father drew her into a lifetime of deception that became one of the most baffling cases in the annals of American true crime.

In and out of hospitals since birth, angelic nine-month-old Morgan Reid finally succumbed to what appeared to be sudden infant death syndrome. Morgan's Texas-born mother, Tanya, a nurse and devoted wife, pulled up stakes with her grieving husband, Jim, and moved on. It was the best way to put the past behind them. Until their son, Michael, a boy who by all accounts was terrified of his mother, began showing signs of the same affliction that stole the life of his baby sister....

On a November morning in 2015, Christopher Jackson waited for his fiancée, Angila Wilder, to pick him up from work as she always did. But this time, she didn’t show - and Christopher’s calls went unanswered. The police found what looked like a scene from a horror movie at their home. The backdoor kicked in. A bedroom splattered with blood. And a pregnant young woman violently stabbed to death.

As a young man, Randall Woodfield had it all; he was a star athlete with good looks and an award-winning student. Working in the swinging West Coast bar scene, he had more than his share of women. But he wanted more than just sex. An appetite for unspeakable violent acts led him to cruise the I-5 highway through California to Washington, leaving a trail of victims along the way. As the list of the dead grew, the police mobilized to stop a twisted killer who had 44 known deaths to his name.

In a quiet community of million-dollar homes and shiny SUVs, the Nyce family projected the very image of success. Dr. Jonathan Nyce, an asthma sufferer, had achieved medical breakthroughs that made him rich - and offered hope to countless people. Michelle's beauty made her an object of desire. And adultery was her husband's worst nightmare.

All Diane Bertalan really knew of her new husband, John, was that he was a widower, he lavished her with gifts, and he preferred to keep his past a secret. What she didn't know was that the FBI had been watching him for years. In the fall of 2000, she found out why - it was a crime that had been haunting authorities for decades. They called it the mystery of the Lady in the Box.