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.

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.

On the morning of July 18, 2014, 41-year-old Florida State law professor Dan Markel dropped his boys off at preschool, hit the gym, and headed home to his quiet, tree-canopied neighborhood. Within seconds of pulling into his garage, two .38-caliber bullets fired from point-blank range were lodged in his brain. His brutal slaying defied explanation.

Two days after Christmas, 2011, Russel Faria returned to his Troy, Missouri, home to find his wife, Betsy, dead, a knife still lodged in her neck. She had been stabbed 55 times in a brutal murder that would set off a chain of events leading to one man's wrongful conviction and imprisonment, another man's death, the revelation of a diabolical scheme, and an astounding miscarriage of justice left unresolved for another 10 years.

Joyce Aparo seemed to be the perfect single mother. She doted on her sixteen-year-old daughter, Karin, encouraging her musical ability and lavishing affection on her. But behind closed doors, Joyce was a terror. For thirteen years, she beat Karin savagely and demeaned her relentlessly. When Karin met the troubled yet brilliant Dennis Coleman, the two fell head-over-heels. But Joyce disapproved—so she had to die.

Loni Ann, Cynthia, Lauren, Cheryl, and Sara seemed to have it all - beauty, wealth, children, and a husband who they believed to be this perfect man - Brad Cunningham. He was handsome, charismatic, and mysterious. They adored him and tried to give him all he wanted. But he wanted everything: sex, money, and it seemed, their very lives. How long would it take before he finally got what he deserved?

Former stripper-turned-suburban-housewife Marjorie Orbin filed a missing person's report on her husband. She claimed that Jay, a successful art dealer, had left town on business after celebrating their son's birthday more than a month before. Jay loved his family more than life itself - and no one believed he would ever abandon them. Authorities suspected foul play

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.

On any Sunday morning in the Florida Redlands, Dee Casteel might have served you pancakes at the IHOP. She was a hard-working, cheerful waitress, one of the nicest people you'd ever want to know. She was also a three-bottle-a-day alcoholic, hopelessly in love with the IHOP's manager, Allen Bryant. Bryant wanted his live-in lover, IHOP owner Art Venecia, dead. And Dee Casteel helped him to arrange it.

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....

The tragic story of Susan Powell and her murdered boys, Charlie and Braden, is the only case that rivals the Jon Benet Ramsey saga in the annals of true crime. When the pretty, blonde Utah mother went missing in December of 2009 the media was swept up in the story - with lenses and microphones trained on Susan's husband, Josh. He said he had no idea what happened to his young wife, and that he and the boys had been camping in the middle of a snowstorm.

Bright, attractive, and both from good families, University of Texas college student Colton Pitonyak and vibrant redhead Jennifer Cave had the world at their beckoning. Cave, an ex-cheerleader, had just landed an exciting new job, while a big-money scholarship to UT's prestigious business school lured Pitonyak to Austin. Yet the former altar boy had a dark, unpredictable streak. When Jennifer failed to show up for work on August 18, 2005, her mother became frightened. Sharon Cave's search led to Colton's West Campus apartment, where Jennifer's family discovered a scene worthy of the grisliest horror movie.

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.

Candy Montgomery and Betty Gore had a lot in common: They sang together in the Methodist church choir, their daughters were best friends, and their husbands had good jobs working for technology companies in the North Dallas suburbs known as Silicon Prairie. But beneath the placid surface of their seemingly perfect lives, both women simmered with unspoken frustrations and unanswered desires. On a hot summer day in 1980, the secret passions and jealousies that linked Candy and Betty exploded into murderous rage.

Joe Gere said he died on the afternoon his 12-year-old daughter Brenda disappeared. It was left to Brenda's mother Elaine to sustain her stricken family, search for her missing child, and pressure the authorities for justice. From the first minutes of the investigation, suspicion fell on Michael Kay Green, a steroid-abusing "Mr. Universe" hopeful, but there was no proof of a crime, leaving police and prosecutors stymied. Tips and sightings poured in as lawmen and volunteers combed the Cascades forest.