From the detective who found The Golden State Killer, a memoir of investigating America’s toughest cold cases and the rewards--and toll--of a life solving crime.

I order another bourbon, neat. This is the drink that will flip the switch. I don’t even know how I got here, to this place, to this point. Something is happening to me lately. I’m drinking too much. My sheets are soaking wet when I wake up from nightmares of decaying corpses. I order another drink and swig it, trying to forget about the latest case I can’t shake.

Crime-solving for me is more complex than the challenge of the hunt, or the process of piecing together a scientific puzzle. The thought of good people suffering drives me, for better or worse, to the point of obsession.

People always ask how I am able to detach from the horrors of my work. Part of it is an innate capacity to compartmentalize; the rest is experience and exposure, and I’ve had plenty of both. But I had always taken pride in the fact that I can keep my feelings locked up to get the job done. It’s only been recently that it feels like all that suppressed darkness is beginning to seep out.

When I look back at my long career, there is a lot I am proud of. I have caught some of the most notorious killers of the twenty-first century and brought justice and closure for their victims and families. I want to tell you about a lifetime solving these cold cases, from Laci Peterson to Jaycee Dugard to the Pittsburg homicides to, yes, my twenty-year-long hunt for the Golden State Killer.

But a deeper question eats at me as I ask myself, at what cost? I have sacrificed relationships, joy—even fatherhood—because the pursuit of evil always came first. Did I make the right choice? It’s something I grapple with every day. Yet as I stand in the spot where a young girl took her last breath, as I look into the eyes of her family, I know that, for me, there has never been a choice. “I don’t know if I can solve your case,” I whisper. “But I promise I will do my best.”

It is a promise I know I can keep.