Paul Holes was starting out in the field of criminology when, one day in 1994, he spotted a filing cabinet in the library of the crime lab where he was working. He opened a drawer, pulled out some files, and discovered the cold case that he would spend his entire career trying to solve. He did it through a trial and error process that involved old-fashioned detective work, new technology, and countless wrong turns before he finally found himself at the Golden State Killer’s front door.