An exploration of the twisted crimes of Joseph James DeAngelo, the Golden State Killer, and the groundbreaking use of familial DNA to crack one of the most chilling cases in modern history. The Golden State Killer case captivated the public and became a true crime phenomenon, spurring documentaries, podcasts like  My Favorite Murder , and even TV shows such as  Unbelievable  and  Mindhunter . This book uncovers the behind-the-scenes work that led to the identification of DeAngelo, bringing an end to his reign of terror and changing the process of criminal investigation forever. With thrilling insights into the science of familial DNA, this book is a must-read for fans of  Making a Murderer  and  The Jinx . True crime buffs won’t want to miss this deep dive into one of the most astonishing criminal cases of the 21st century, combining cutting-edge forensic science with a truly evil villain. Brad Hunter is the National Crime Columnist for The Toronto Sun. Previously he worked for the New York Post and his work has been published in newspapers and magazines around the planet. He lives in Hamilton, Ontario, Canada and is the author of Inside the Mind of John Wayne Gacy.