A Book A Week

I’m a sucker for a good murder mystery. There’s something about the thrill of peeling back the layers of a well-crafted whodunit that grips me like nothing else. So when I stumble upon a new crime novel—especially one as compelling as Head Cases by John McMahon—I tend to read it straight through, determined to reach that final reveal. The premise of McMahon’s latest, which also launches a new series, first caught my attention when it was published in January. For whatever reason, I didn’t pick it up until now, but I’m thrilled I finally did.

When FBI Agent Gardner Camden signed on to join the agency’s quirky Pattern and Recognition (PAR) unit, he knew he’d be facing the kinds of cases no one else could crack. He’s built his career on untangling the impossible, using his gift for puzzles to bring clarity to investigations that defy logic. If that were all the job required, Gardner would be just fine. Unfortunately, the very traits that make him invaluable in the field make him a liability everywhere else.

Gardner struggles with the human side of investigations. Social cues that others instinctively pick up on sail right past him, stalling his career and straining his relationship with his seven-year-old daughter. As a result, Gardner and his team are typically confined to cold cases, working quietly from behind their desks. But that changes when DNA links a current murder victim to a serial killer long presumed dead. When a second victim appears, and a clear pattern emerges—along with clues and riddles seemingly crafted just for Gardner—the PAR team is thrust into an active investigation. No longer buried in case files, they’re sent into the field, following a killer who appears to be playing a very personal game.

Head Cases is the kind of hardboiled crime mystery that feels both timeless and timely. John McMahon sticks to the familiar conventions of the genre, then twists them into chilling new directions. The villain here—aptly named Mad Dog—sent a genuine shiver down my spine. He’s the perfect foil to McMahon’s hero, Gardner Camden, and watching the two engage in a cat-and-mouse battle of intellect is a pure thrill.

McMahon smartly balances the high-stakes suspense with grounded character work, deftly exploring Gardner’s personal life while thoughtfully examining the challenges of living somewhere on the spectrum. I couldn’t help but care deeply for Gardner and his family, which only heightened the tension as Mad Dog began making the case increasingly personal. All told, Head Cases is an excellent crime thriller and a must-read start to a new series. I can’t wait to see where McMahon takes Gardner next when the sequel arrives early next year.

For more information, visit the author's website, Amazon, and Goodreads. 

(2025, 100)