For twelve years the Golden State Killer terrorized California, stalking victims and killing without remorse. Then he simply disappeared, for the next forty-four years, until an amateur DNA sleuth opened her laptop. In I Know Who You Are, Barbara Rae-Venter reveals how she went from researching her family history as a retiree to hunting for a notorious serial killer—and how she became the nation’s leading authority on investigative genetic genealogy, the most dazzling new crime-fighting weapon to appear in decades.

Rae-Venter leads readers on a vivid journey through the many cases she tackled, often starting with little more than a DNA sample. From the first criminal case she ever solved—uncovering the long-lost identity of a child abductee—to the heartbreaking story of the Billboard Boy, whose skeletal remains were discovered along a highway, to the search for the Golden State Killer, Rae-Venter shares haunting, often thrilling accounts of how she helped solve some of America’s most chilling cold cases in the span of just three years.

For each investigation, Rae-Venter brings readers inside her unique “grasshopper mind” as she analyzes DNA data and pores through obituaries, marriage records, and old newspaper articles. Readers join in on urgent calls with sheriffs, FBI agents, and district attorneys as she details the struggle to obtain usable crime scene DNA samples, until, finally, a critical piece of the puzzle tumbles into place.