Updated with dramatic developments and new murder charges, filed in the coldest of cold cases, to keep a serial baby-killer behind bars. This tale is every parent's worst nightmare: the horrifying account of a Texas nurse who killed children under her care, and the hospital that covered it up.

After his December 2003 arrest, registered nurse Charlie Cullen was quickly dubbed "The Angel of Death" by the media. But Cullen was no mercy killer, nor was he a simple monster. He was a favorite son, husband, beloved father, best friend, and celebrated caregiver. Implicated in the deaths of as many as 300 patients, he was also perhaps the most prolific serial killer in American history.

Colorado, 1976. When Reverend Mike Fuller and his beautiful wife, Sharon, arrive in the sleepy town of Rocky Ford, local residents think something’s off about the new couple. The God-fearing minister is gruff and cold, while charismatic Sharon has her husband wrapped around her finger.

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.

Roger and Penny Scaggs seemed a poster couple for family values. Evangelical Christians living in booming Austin, Texas, in the mid-1990s, they were respected leaders in their church and community. As Roger diligently worked his way up the high-tech corporate ladder, Penny kept a pristine home and coached similarly devout young women on how to be perfect wives. But on a windy March evening, this godly woman met the devil head-on.

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.

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.

On January 7, 1994, residents of the Berkshire Hills woke up to a typical snowy winter day in the majestic woods of Western Massachusetts. The quaint New England towns, the idyllic scenery and the people who lived there could have stepped out of a Norman Rockwell painting.

In November 1987, a young couple on an overnight trip to Seattle vanished without a trace. A week later, the bodies of Tanya Van Cuylenborg and her boyfriend Jay Cook were found in rural Washington. It was a brutal crime, and it was the perfect crime: With few clues and no witnesses, an international manhunt turned up empty, and the sensational case that shocked the Pacific Northwest gradually slipped from the headlines.

After Hurricane Katrina struck and power failed, amid rising floodwaters and heat, exhausted staff at Memorial Medical Center designated certain patients last for rescue. Months later, a doctor and two nurses were arrested and accused of injecting some of those patients with life-ending drugs.

William Neal, who called himself "Wild Bill Cody," was seductive and skillful at separating love-struck women from their money, and ultimately, their lives. Apprehended by police, Neal, who proclaimed himself “better than Ted Bundy,” pleaded guilty to three murders then insisted on representing himself at his death penalty trial. But the psychopathic killer found himself up against the incredible courage of his one surviving victim.

In the tradition of The Glass Castle, Educated, and Heartland, Neal Wooten traces five decades of his dirt-poor, Alabama mountain family as the years and secrets coalesce.

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.

Returning to practice after a suspension for stealing opioids, a young doctor takes the only job he can find: a post as a physician at the struggling St. Luke's Hospital in east London. Amid the maelstrom of sick patients, overworked staff and underfunded wards, a more insidious secret soon declares itself: too many patients are dying. And a murderer may be lurking in plain sight.

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.