This reminded of how much I love police prodecurals, quirky and brilliant detectives, and lots of tiny details that all have a meaning in the end. Loved it so much, and I really hope this continues as a series. The main character/detective was so real, and had me nearly in tears in one scene where his emotions come to the forefront in such a relatable way. All the stars.

John McMahon has given us an American version of Mick Herron's Slow Horses. Here we have a team of FBI agents with marks on their records and have been assign to a special unit known to other agents as Head Cases. This first installment sets us up with teasers on the histories of an interesting cast of characters that we'll have to read the next book find out more. And we will.

The reader follows along with the main character and observes the action, but we're not given insight as to all the inner working of the investigators. But it still works. There's so much going on that you are still engaged in the case and action that you don't miss the ability to figure out the puzzle as you read. You read as fast as you can just to catch up with the investigators. Or maybe the information is their for the reader and I just missed it as I was caught up in the storyline and didn't also feel the need to crack the case. It's a fun ride.

Sensitive readers should know there's a few scenes with vivid anatomical descriptions.

Perfect for readers looking for a new, fast-paced investigation series with a meta-story that will take several books to dole out the backgrounds of an interesting cast of characters.

One of those books that you know instantly you are going to love, and this book validated that gut feel.

A serial killer murdering serial killers, a nonsocial genius with a didactic memory, and his brilliant mother, suffering from dementia. Reminds me of Criminal Minds and I am here for it!

I really enjoyed the entire book, the little clues to sort out, and the genius of Camden Gardner. It’s my first time reading this author and I’ll definitely be catching his next book!

Thanks to Minotaur and Net Galley for this ARC and John McMahon for a great story

I have been on a detective /FBI kick lately. I was not familiar with the author., but that did it stop me from picking this up.

This is a slightly different take on FBI investigations. This is about a group of agent misfits or contrarians who think and analysis outside of the box. They look for unlikely patterns in solving a serial killer who brutally and strangely mutualates the victims bodies.

I enjoyed this quick read. It is set up to be a series. It will be fun to see how the characters evolve.

Thank you, NetGalley, for an advanced copy.

Thanks to NetGalley and St. Martin's Press for the ARC!

This novel felt as if I was reading the Criminal Minds team taking on Dexter, a serial killer murdering serial killers in grisly fashion. A group of quirky FBI agents from the department where careers go to die, come together under the lead of Gardner, a man who loves puzzles and finding patterns in cases, in a fast-paced police procedural. It was a real page-turner with layers, twists, turns, and some heart (among other organs). At times, the novel felt a little uneven by including moments of depth, that didn't have enough breath to them. Character backgrounds felt a little rushed and glossed over which would have helped the reader connect to them and feel a lot more in those deeper moments.

Overall, did it feel highly original? No. Was it a police procedural we've become familiar with on weekly TV? Yes. Does it make it any less fun? Absolutely not. The plotting was well-done and kept me guessing up to the very end as to why all of this was happening and what the ultimate goal of the murder was. I probably won't remember this book by the end of 2025, but it was still an enjoyable read.

This is a two-book deal for McMahon with the second novel in the series expected early next year and I'm excited to see how our "head cases" in PAR deal with another puzzling case.

Reading this was almost exactly like watching an episode of Criminal minds, maybe like one of the two part episodes. We follow FBI agents that are banished to PAR (patterns and recognition) for not conforming to the societal expectations and politics in the FBI, sort of like a group of Dr. Reids, each with their own pattern based super abilities. The entire book was fast paced and clever, if you even remotely enjoy Criminal Minds this is the book for you. The audiobook was also really well done and the narrator does a great job of embodying the main character. This is listed as the first in a series so I will definitely be continuing.



Thanks to Netgalley, John McMahon, and Minotaur Books for this e-ARC that I chose to read and review

This is the first book I’ve read from McMahon, and as suspense goes it’s a cut above the average. While parts of it were admittedly predictable, for the most part it kept me guessing and held my interest. If you elect to read Head Cases, you will probably figure at least portions of it out as you go along; I certainly did. But it doesn’t all fall into place until near the end of the book, and for me that was a nice change, as the “mystery” is usually pretty much a no-brainer.

Character development for the main protagonist of Gardner Camden was decent, if not extensive, but it was notably shallow for the remaining cast of characters. The reader learns little about Frank and his strange habit of never actually eating during meals with the team, for example, although McMahon makes a point of highlighting it at least three times. A little background is shared about Jo (aka Shooter), but virtually nothing about either Cassie or Richie or the rest of the extended cast. It may well have been my take, but the characters I liked most were among those the reader sees the least (Camden’s mother and his ex-wife), and I’d have liked to have seen more on both. If the author makes it a series, as seems likely, hopefully McMahon delves more deeply into all of these characters.

There were several errors that should have been caught in editing that I saw without really looking: at least one error each in continuity, spelling, and word choice. I tend not to look for such things, and in fact actively try not to see them because they detract from my enjoyment of the book. The fact that these were so readily apparent is probably indicative that the book really needs at least one more good editorial sweep, but hopefully they’ll be resolved prior to release.

Overall it was a quick, fun read, and I’d recommend it to a fan of the genre looking to kill a few hours. It’s a decent addition to the police procedural genre and worth taking for a spin.

Disclosure: I received an ARC of this book from the publisher via NetGalley and am leaving a voluntary review.

Neurodivergent FBI agent Gardner Camden is part of the PAR (Patterns and Recognition) team. He works with a group of equally quirky officers, each with a special skillset. Each has had their issues within the FBI and have been sent to PAR as a last resort. They are the misfits or "Head Cases" of the Agency. Now they are being assigned to work on a serial murder investigation tracking down a murderer of criminals.
This was a fun read. I loved all the team members of PAR and felt that their quirkiness added a levity that the book needed. The mystery runs deep in this book and I loved how it all wrapped up. I'm very excited to read more in this series.
The narrator for the audio book, William Damron is excellent. He is able to give the characters different voices in way that works and also keeps the story flowing.

“Head Cases” by John McMahon follows PAR, the Patterns and Recognition unit of the FBI. Agent Gardner Camden is shocked when a criminal he thought was already dead is discovered murdered. When a pattern emerges of someone doing away with bad men, Camden begins a cat and mouse game with a serial killer who thinks he’s doing the FBI a favor. This fast-paced read is one I couldn’t put down!
I absolutely loved this book. The characters, the plot, everything was hitting the mark for me. When a book reminds me of my favorite tv show (Criminal Minds), it’s definitely doing something right.
While I love a good mystery/thriller, this book also set up a lot of interesting subplots that will keep me wanting each new book in the series (Camden’s daughter, his partner, his ex wife, etc). I’m genuinely sad that this book isn’t out yet because that means I have to wait even longer to see what comes next!
In the end, this book obviously gets 5 stars from me. I was on the edge of my seat from the beginning, and while I wanted to solve the case I didn’t want the story to be over! This team is one I want to stick with for a while and then some.
Thanks to Minotaur Books and NetGalley for an ARC!

I absolutely LOVED this book! I will be this book to add to my collection and also the second book of this 2 part series.
If you are a Criminal Minds, BAU, Spencer Reid fan meets Dexter (without the Dexter gore), then you will enjoy this book. I enjoyed the thrill of the hunt of who and how and the why. I can not wait for the second book of this 2-part series to come out!

My thanks to Net Galley and St Martin s for allowing me to review this arc.

Loved this! Highly recommended! I hope this continues as a series with these characters.

FBI agent Gardner Camden and his team track down a serial killer that kills serial killers. Very intelligent and engaging to read. Good writing. Some graphic parts but really enjoyed.

electrifying and thrilling thriller that was very enjoyable. i found the protagonsit a very effective character, and tracking down the murderer was certainly w.ell written. 4 stars. tysm for the arc.

If you are a fan of Sherlock Holmes, Dr. House, or Will Trent, you will want to read this. This is not a cozy mystery; there are some graphic descriptions of the crimes that might be shocking if you are new to the thriller genre. As a seasoned thriller reader, though, they are pretty mild.

The main character, Gardner Camden, is neurodivergent and possibly autistic (probably) but is NOT portrayed in a cheesy, stereotypical way. The other characters were distinct and easy to keep track of. The pacing was steady and quick.

I'm excited to see there will at least be a sequel but I'm hoping there will be demand for many more! This is EXACTLY the type of book I reach for when I'm not quite sure what I'm in the mood for and I can't wait to recommend this one to anyone who'll listen!

I absolutely adored this book - 5 STARS - the main gist of the book centers around a group of "misfits" within the FBI that are tasked with trying to solve a series of murders. The characters were well written and the book flowed well. I hope to see additional books with these characters

An elite division of the FBI is tasked in finding a serial killer who is murdering serial killers. An intricate plot with likeable characters made this a page turner for me. I loved seeing quirky characters portrayed in such a positive light.

Agent Gardner Camden is part of the FBI’s elite PAR unit (patterns and recognition). Camden excels at solving puzzles and along with a mathematician, a sharp shooter and a computer analyst the group makes the task force continue like clockwork. Now they are faced with their toughest challenge yet: the murders of bad men.

Head Cases is a good solid crime procedural in which team of investigators works tougher to solve elaborate puzzles. I enjoyed the continual action (and misfortune) as they worked their way through cat and mouse scenarios with the perpetuator. The PAR unit is sure to remind Criminal Minds fans of the BAU (behavioral analysis unit) and it is written here excellently. If you are a fan of detective/police thrillers, this book will be right up your alley. I enjoyed this one and rate it four stars.

I received this advance copy from the publisher via NetGalley in exchange for an honest review and feedback.

This was such a fun read/listen. The intricate plot kept me interested the entire time, and I never guessed what was going to come next. The characters were all very interesting. I would love to watch this as a TV series; it felt a little Dexter-esque. I will definitely be interested in continuing this series. Solid 4.5 stars.

An elite division of the FBI is tasked in finding a serial killer who is murdering serial killers. An intricate plot with likeable characters made this a page turner for me. I loved seeing quirky characters portrayed in such a positive light.

Head Cases follows a group of FBI agents with unique skills who solve tough cases that no one else can. Someone is killing other serial killers (🤯), and this group is tasked with finding them.

Overall, I really liked this one. I’ll never say no to a book about serial killers, and this was a fast-paced read that kept me engaged. I loved the PAR unit members and their mysterious backstories.

Head Cases reminded me a lot of Criminal Minds, but if the team was lead by Dr. Spencer Reid (which is a huge compliment BTW).

This book comes out on January 28 - definitely recommend checking it out! (Thank you @minotaur_books for the #gifted copy)

Sign me up for any future releases of the PAR Unit sequels—this is my new obsession! If you’re a fan of FBI dramas, Criminal Minds, or Profiler, and you also enjoyed the sharp wit of Slow Horses, you’ll love this book. The PAR Unit is a unique, unconventional FBI team made up of socially awkward, underrated, yet highly skilled individuals who struggle to follow rules and office politics but excel in solving the unsolvable.

The only thing missing from this book is a touch of sarcasm. If you’re expecting an eccentric, narcissistic leader like Jackson Lamb (brilliantly portrayed by Gary Oldman in Slow Horses), you won’t find one here. But don’t worry—FBI Agent Gardner Camden, the main protagonist, is far more likable and relatable. Unlike Lamb, Gardner is younger, clean-cut, and doesn’t rely on greasy food or alcohol to function (and yes, his socks are hole-free as far as I can tell!).

Gardner is a truly unique character. Socially awkward and possibly neurodivergent, he’s a master of puzzles, able to see patterns others miss. He is dedicated to doing what’s right, even at great personal cost—dividing his family, losing full custody of his daughter, and sacrificing his promising career. But given a second chance, he’d likely make the same choices. Now, he works with a team of outcasts in Jacksonville and only gets to see his daughter, Camila, for a few days at a time. She lives with her grandmother in Miami, who openly despises him for reasons Gardner can’t dispute.

The team members of PAR Unit are just as compelling. Cassie, Gardner’s partner, recently transferred after an incident with her previous superior and is as detail-oriented and brilliant with numbers as he is. Then there’s "The Shooter," a blonde, eccentric weapons expert who might just be my favorite team member. Frank, their leader, gives off "younger Denzel Washington" vibes but seems to take a back seat to Gardner on this case for mysterious reasons.

Rounding out the team is Richie, a dark-haired, highly skilled rookie in his mid-twenties. Suspiciously, his personnel file is sealed, something that quickly catches Gardner’s attention.

What makes the PAR Unit so extraordinary is their ability to detect patterns and solve puzzles ten times faster than the average FBI agent. Unfortunately, their colleagues call them “Head Cases” behind their backs, and the unit is at risk of being shut down. Their current assignment—a cryptic and high-stakes case—could make or break their careers.

A serial killer with a God complex is targeting other serial killers who escaped justice, killing them in the same gruesome ways they murdered their own victims. This killer thrives on puzzles and patterns, and he’s determined to draw Gardner into a dangerous game. Gardner must outthink the killer while refusing to play by his rules. Thankfully, he has a team of out-of-the-box thinkers to help him stay one step ahead and dismantle the killer’s plans. But can they win this deadly game of cat and mouse?

This book is a smart, fast-paced thriller with well-rounded, unconventional characters and an exhilarating plot. The satisfying conclusion left me urgently wishing for a sequel!

I’m giving this five stars for its nerdy, quirky, and brilliantly unconventional team!

Many thanks to NetGalley and St. Martin’s Press/Minotaur Books for sharing this brilliant crime thriller’s digital review copy with me in exchange for my honest thoughts.