“A true-crime masterpiece written by a cold-case-cracking master. Barbara Rae-Venter’s investigative DNA work has revolutionized the way law enforcement hunts serial killers.”—John Douglas, New York Times bestselling co-author of Mindhunter

“Barbara Rae-Venter isn’t just the genealogy expert who helped capture the Golden State Killer—she’s an unsung hero who has given murdered women and children their faces and names back, recognizing that their lives mattered.”—Maureen Callahan, New York Times bestselling author of American Predator

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.

I Know Who You Are captures both the exhilaration of the moment of discovery and the sheer depth of emotion that lingers around cold cases, informing Rae-Venter’s careful approach to her work. It is a story of relentless curiosity, of constant invention and reinvention, and of human beings striving to answer the most elemental questions about themselves: What defines identity? Where do we belong? And are we truly who we think we are?