Simon’s groundbreaking account of a year in the life of Baltimore detectives gets adapted by cartoonist Philippe Squarzoni in Homicide: The Graphic Novel, Part 1 (First Second, July).

Homicide is a crime book, but it’s not the expected for true crime. What did you do that was different?

I was interested in what it meant to work murders in a city of constant violence. Before I sat down to write, I read Tracy Kidder and Ball Four by Jim Bouton; those were the kind of books I was trying to emulate. I was looking for the assembly line and what that does to the people doing the job. I wasn’t looking for who done it. The idea was just stand around and watch. Become furniture and stay long enough so that people stop bullshitting.

Being a newspaper reporter taught me where the pressure points were—the homicide unit, the courthouse. As a white kid from the Washington suburbs, I’d learned that I had to listen to different kinds of people. That was exhilarating. I wasn’t trapped in my head. I could go out and acquire other voices.

You’ve adapted other writers’ books for TV, including Generation Kill. What was it like having a cartoonist adapt yours?

As a filmmaker, I understand that original work cannot be simply replicated in other mediums. I tended to respect his medium as being different than my own. He knew what he had room for and how he had to pace it. You have to let go.

What kind of credibility did you have with the detectives as a 27-year-old reporter?

They took a vote and only three guys wanted me to be there. The rest thought it was a terrible idea. But, it not being a democracy, they put me in the unit anyway. Nobody was hostile. They got used to me. One guy, Terry McLarney, we were drinking at the bar and he said, “I see what you’re doing. This isn’t really about the cases. This is about us.” I said, “Don’t tell anyone.”

These guys got used to you?

A lot of reporters are not willing to play the fool. Nothing’s more charming than making yourself an idiot. It’s an interrogative technique for cops. It’s Colombo.

I should tell you that I don’t regard the book as being empathetically pro-police. It’s more an ethnography of these guys and the way they view the world. Obviously, I don’t believe all cops are bastards. But neither do I believe in “back the blue.” I’m against the drug war and I’m against mass incarceration. I’m for murders being solved.

Did the guys like the book?

The French edition came out first, and I sent a set to each of the detectives who were still around. I got some very funny responses back. They were fascinated. There was a lot of consternation that none of them spoke French. One of them sent back a note that just said, “Merde.”