Chuck Hogan knows his way around a crime novel.

The author made his literary debut 20 years ago with The Standoff and followed that up with several more novels, including Prince of Thieves, the 2004 bank-robbery thriller that was adapted into Ben Affleck’s critically acclaimed film The Town. He also tried his hand at horror, collaborating with filmmaker Guillermo del Toro on the Strain trilogy of novels, which formed the basis for an FX television series.

Hogan’s latest book, The Carpool Detectives (Random House, July 29),  is another thriller designed to keep readers guessing. It tells the story of four women in Southern California who become obsessed with a cold case: the suspicious death of a couple found near an SUV at the bottom of a canyon. The women, all mothers navigating their lives during the early days of the Covid-19 pandemic, go to work investigating the case, talking to detectives and family members of the dead husband and wife, and painstakingly going through records, desperately trying to find who might be responsible for the slayings. Eventually, to the astonishment of law enforcement—and themselves—they solve the case.

Here’s the twist: It’s a true story. The mothers-turned-detectives are identified in the book by their real first names, although the identities of everyone else involved, and specific details about the crime, have been changed.

The women are still friends, and Hogan says that their relationship is just as remarkable as the fact that they were able to solve the case. “Two years earlier, three of them were stay-at-home moms,” he says. “One of them was still working, but they weren’t doing anything like this. Finding friends, finding themselves, and taking on this entirely new persona as a bona-fide investigation team is really extraordinary. They have a really special connection.”

Hogan talked about the book via telephone from his home near Boston. Our conversation has been edited for length and clarity.

How did you first come to learn about these four citizen detectives on the other side of the country?

It came from my literary agent, who is also my manager. The moms had a friend who was a television director who’d been following the case from afar and eventually convinced them to tell some people about this. He and I were at the Edgar Awards, and he told me about it. Anybody could see this is a one-of-a-kind story. It’s almost too incredible. I think if I had pitched it as a novel, editors would have said, I don’t know; that seems like a bit of a stretch. On top of that, I Zoomed with the four women, and they’re very impressive people themselves. They pursued this completely; they just became obsessed with it. They weren’t Instagramming their investigation; they weren’t trying to get a podcast going. They just really wanted to find out what had happened. I honestly never saw myself writing a nonfiction book ever, but the story was just too amazing not to be a part of it.

Were they initially receptive to the idea of you writing about it?

They were concerned about their safety and their families’ safety. Two of the women weren’t sure that they wanted to go along with it at all. But part of my job, as I saw it, was to make sure that they were comfortable and to obscure the actual details of the original case while preserving precisely their investigative steps along the way. That was a challenge but also a big responsibility of mine to see that through.

What was the process like, having come from a background of fiction and screenwriting, to research a nonfiction book?

There was a real learning curve for me. They had done a lot of the research and basically preserved it for me. I thought I would have an easier time of it, but I had to go through all of it and find my own way through their investigation, not by reinvestigating it but by tracing their footsteps. In terms of practical things, they took me to some of the actual crime scenes and other locations, which was really helpful. And they made hundreds of pages of their own contemporary text messages available. I could really feel at times their exultation at a break in the case, as well as their frustration. We reproduce some of that in the book, which was really helpful in terms of charting their course through this long, at times frustrating, but ultimately successful investigation.

What was your relationship with the true-crime genre before you heard of this case?

I think I’m like most people: A good true-crime documentary? I’m in. I don't read a lot of true-crime books, and I’m not much of a podcast person. I’m more of an audiobook person. Obviously, there are some incredibly interesting crimes out there, but I’m always more interested in what’s behind them. Normally, that has to do with the perpetrator, but here I was much more interested in the four women. They had no personal attachment to this case whatsoever. What was it about this case that spoke to them? What were they looking for as they were trying to bring answers to this other family with whom they became emotionally involved in the course of investigating? There was no money changing hands. No one had hired them. They didn’t know anyone involved in it.

A lot of people who read true-crime are women, so I thought it was interesting to see four women on the other side of it, only one of whom was a true-crime fan—that’s Samira. The others were interested in a good story no matter what form it takes, but to have these women actually doing interviews and canvassing really interested me.

Do you think that this investigation would have happened in the same way without the Covid-19 shutdowns?

No, I don’t, and neither do they. I think in a strange way they benefited from it, because people were at home and available—they would answer their phone, and they were looking for something to do. In other words, Sure, I’ll spend an hour with you on the phone talking about this strange thing that happened to my boss 15 years ago that I’ve never forgotten and that I would love to get answers to. It was limiting in terms of [not] being able to physically visit certain places they wanted to travel to, but I think it allowed for much more. It gave them time, as busy as they were, being stay-at-home moms, at a time when everyone was staying at home. It was also something, I think, that they really looked forward to as a distraction from that terrible period in everyone’s lives.

Do you think this will be your last nonfiction book?

I do. [Although,] the four women have been working on this other case for quite some time, and if they solve it and were interested in doing something else, there’s no way I could say no to them because we’ve been through this together. But no, this very much feels like a one-and-done for me. I’ve scratched that itch, and I’m looking for the next challenge.

Michael Schaub is a contributing writer.