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. Cullen's murderous career in the world's most trusted profession...

"Acclaimed crime historian, podcaster, and author of American Sherlock Kate Winkler Dawson tells the thrilling story of Edward Rulloff-a serial murderer who was called "too intelligent to be killed"-and the array of 19th century investigators who were convinced his brain held the key to finally understanding the criminal mind"-- Provided by publisher.