I didn't know what to expect when I picked this one up but I'm so thrilled that I read it. Head Cases features Gardner Camden. Camden is a genius working for the FBI. He is called to a home with his partner after a man is found murdered. The surprise? The body is that of a serial killer that Camden had investigated in the past and was declared dead 7 years ago. Things take off from there. I loved the mystery behind all of this and how it all unravels. Camden is brilliant and quirky. I loved this character. He is multi-layered and is really impacted personally by the events that roll out and so there is character growth that I don't usually see in this type of novel. We get to see him as a friend, a father, and a son. He was just so interesting and kept me engaged and captivated the entire time. I had not read anything from this author but would love to read more from them in the future, especially with the characters found in this book.

McMahon's writing style is engaging, and his narrative technique keeps you on the edge. I don't read many police or FBI procedurals, but I have to rave about how much I loved "Head Cases!" It felt tailor-made for me. Typically, I shy away from book series because waiting for the next release is challenging. Yet, here I am, dying to get my hands on the next book in this exciting series!

PAR (Patterns and Recognition) is an incredible little unit of brilliant and enigmatic members working as hidden assets within the FBI, tackling cases others can't crack.

The standout for me is Agent Gardner Camden. He's a delightful blend of socially awkward whiz and quirky charm that I can't get enough of. I got a Spencer-vibe (Criminal Minds) from him! It's a shame that his uniqueness leads to some bumps along the way, both in his personal life and career. While the rest of his team is fantastic, Gardner truly steals the show. I can't wait for future books to peel back the layers of his complicated backstory!

In this first thrilling installment, an old case resurfaces: a vigilante has taken it upon himself to eliminate serial killers. A serial killer hunting other serial killers—how mind-boggling is that? It's a concept that really makes you think—almost like he's assisting the PAC Unit. I mean, don't they have more pressing matters to attend to? 🤣 The moral dilemma is truly thought-provoking!

As I followed the team through their investigations and got a peek into their thought processes, I felt like part of the gang. Their friendship and shared goal of solving these tough cases pulled me right in. If you're a fan of shows like Criminal Minds, I think you'll find "Head Cases" just as captivating and enjoyable as I did!

Thank you to the author, Minotaur Books, and MacMillan Audio for the ALC and ARC provided through NetGalley and Google Play. All opinions are my own.

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HEAD CASES is the first book I’ve read by author John McMahon. The book is the first in an expected series about a specialized FBI group that solves particularly challenging cases. The characters are quirky and engaging, the case itself is complex enough to sustain an entire book and the book is particularly visual and well-suited to a TV series. This will be a series worth following. I received my copy from the publisher through Netgalley.

This gave some definite Criminal Minds vibes and I was so here for it. Gardner Camden reminded me a lot of Spencer Reid with his ability to see patterns and analyze situations. I love the eclectic cast and how larger than life they feel. Some elements felt predictable, but the overall plot was excellent. I cannot wait to see where this team goes next.

⭐️⭐️⭐️⭐️

Thank you to the publisher and @netgalley for the ARC and ALC.

This is a clever contemporary murder mystery and a solid police procedural type of book with a cadre of interesting characters that come to life on the pages. Puzzle lovers and crime solving enthusiasts will want to check this one out.

This book is a well thought out crime thriller that also does a very good job of laying the groundwork for the next step with these characters and their team of crime solving agents. It reminded me of a few TV shows, such as Sherlock, The Mentalist, Mindhunter, and High Potential. I am definitely interested enough to want to read the next book in this series.

Many thanks to St. Martin's Press - Minotaur Books and NetGalley for giving me the opportunity to read a digital ARC of this book. All opinions expressed are my own.

I really enjoyed this and am glad there will be another installment. I’m going to add McMahon’s other series to my TBR list too.

I feel like this hits the ground running, there’s no lead up to the characters or the case and I like that. There’s a great balance between the characters, who I enjoyed and can’t wait to get to know better, and the case itself. I was invested in the process of putting the case together. It’s so intricate, I can’t guess at how it will come together, and I love getting caught up in the details of how they find the information and put it all together. All around, this is the kind of series that I would keep coming back to. Looking forward to the next one.

It’s a good week for thriller readers with the release of James Byrne’s Chain Reaction, Andrew Welsh-Huggins’ The Mailman, and John McMahon’s Head Cases. McMahon might be known to some readers as the award-nominated author of the P.T. Marsh thrillers, including The Good Detective. Now, he launches a new series featuring an unusual group of agents at the FBI. The first book is Head Cases.

There are four people on the Patterns and Recognition team for the FBI, a group that identifies peculiarities, solves puzzles, and highlights them, and then hands the case off to other groups in the FBI or law enforcement. FBI agent Gardner Camden is able to easily solve riddles and puzzles, but he needs clues in social situations. His mother, a psychiatrist, gave him advice and helped him find those clues.

PARs latest case sends the group directly into action. Gardner’s boss meets the team in Texas where a body has been found. Identification of the victim flagged Gardner Camden’s name because he identified the body as dead in a fire seven years earlier. Ross Tegnion was the primary suspect in the murder of thee in Florida until he supposedly died in a fire at his house. Now, his body has turned up in Texas.

But, it’s a second victim, this one in New Mexico, that starts the team on a chase. Barry Fisher was just released from prison when he was killed. It seems “A serial killer was murdering serial killers.” And, the new killer is trying to attract Gardner Camden’s attention.

At times, the details involved in the investigation became a little heavy, but the PAR team is a fascinating combination of misfits, led by Gardner Camden. They all have strengths and weaknesses, and Gardner, as narrator, is the most flawed. It will be interesting to see if future books focus on Gardner Camden or other members of the team. Since PAR is made up of an analyst, a shooter, and a rookie, along with Gardner and his boss, there is room for additional exploration. Despite the details that can be a little graphic or a little too descriptive at times, Head Cases is a welcome addition to the group of books featuring those who hunt killers.

Head Cases is a heart-pounding story about a special group of FBI agents, called the Patterns and Recognition (PAR) unit, who chases after a serial killer who hunts serial killers.

The story is so thrilling and I couldn't wait to find out what happens next. The puzzles are tangled together, and the highly analytical agents untangled each of them and revealed the truth behind the whole case and the large web of history behind it. I loved how the author took us on the satisfying journey of solving the puzzle just like we are part of the team, without the feeling of the narrator intentionally withholding information just to create suspense.

The main character Gardner Camden is an analytical genius with an affinity for puzzles. But instead of making him an oddball isolated in life and set to his ways, we can see him trying to understand the world and trying to fit in. His struggle and journey is another highlight along side the case.

I highlight recommend the book for anyone with a love for puzzles!

“Brilliant freaks” make up the PAR (Patterns and Recognition) unit in the FBI. They’re quite a motley crew of experts, pegs that don’t fit anywhere else, led by Agent Gardner, a brilliant yet flawed neurodivergent protagonist.

This story has it all—puzzles, twists and turns, suspense, forensic credibility, compelling characterization, excellent dialogue, a solid plot with moderate pacing, and some heart thrown in the mix, too. This is book #1 in this new series and I’ll be looking for the next one.

If you enjoy intelligent FBI serial killer fiction that’s not predictable and still manages to wrap up the case to the reader’s satisfaction by the end, you’ll enjoy this book.

4/5 stars

4.5 stars

The PAR (Patterns & Recognition) Unit at the FBI is usually relegated to cold cases within the Bureau. But when an old case he worked gets brought back into the spotlight with a new murder and a DNA match that makes no sense, Agent Gardner Camden is put in charge of the small PAR team of brilliant yet eccentric agents who are also being thrust into that spotlight for the world to watch. As the case grows in scope, Camden becomes the principal target of the serial killer they're trying to apprehend who always seems to be one step ahead. What can the PAR team do to protect the people they love - as well as their FBI colleagues - while desperately trying to solve this terrifying game of cat and mouse?

In the realm of crime fiction it's incredibly difficult to avoid feeling derivative in this day and age - the book and television market is heavily saturated with crime thrillers, police procedurals, and true crime documentaries. Head Cases did an excellent job at telling its story, maintaining good pacing throughout and building up great tension. Most of the characters were well fleshed out, though it would've been nice to get some more backstory on a few of the more enigmatic ones; I'm assuming that will likely be happening soon as this is listed as PAR Unit, #1 so it seems the author has more coming down the pipeline. If you're a fan of shows like BONES, Criminal Minds, Law & Order: SVU, Dexter, etc. you will likely see myriad points of similarity in Head Cases. But I think that with these particularly nuanced characters and other interesting storylines to come in the future this is certainly a worthwhile new soon-to-be series to sink your teeth into.

Thanks to NetGalley, author John McMahon, and St. Martin's Press for giving me access to a free digital ARC of this book to read and review. All opinions are my own and are provided here voluntarily.

If you love criminal minds or any gritty murder shows, you will loooove this! The main character reminded me of SVU and the premise was very cool. I’m not sure if it was just a dude book or a debut, but it felt slightly unedited but it was still a very fun read and I highly recommend if you like police procedural / Monk coded mystery thrillers.

This was a fast paced entertaining thriller! I enjoyed the group of characters but really didn’t feel an attachment to any of them so it left me wanting a bit more depth from the characters. The plot was addictive and fast paced with a lot going on from start to end and I loved how the author was able to give the information about the investigation in a way that felt easy to understand and entertaining! Definitely recommend for all the Criminal Minds lovers!

Because I feel confident in my book selection abilities (I have vast reading experience, I know what I like, and I know how picky I'm feeling/how open I am to trying something new-to-me at any given time) I try to restrict my pre-reading information exposure to the most basic of plot summaries—and little, if any, of others' opinions. I often make notes while I'm reading. This time, post-reading review and research of these notes yielded super-satisfying results. Here are a couple:

Note to self: Excellent narrator. Have I heard him before?
Research results: Without reviewing even half of Will Damron's considerable number of credits, I was able to confirm that I have heard him before, including reading Midnight in the Garden of Good and Evil, by John Berendt, and A Matter of Will, by Adam Mitzner. [This paragraph does not apply to this edition of the book. I tandem read with the audiobook.]

Note to self: Hope there will be more.
Research results: Great news—Head Cases is a series debut! As far as I can tell, this is only McMahon's fourth novel—the first three forming a different series.

The story is reminiscent of the television versions of Dexter, Slow Horses (of which I have also read two installments), and Psych (the third for the keen powers of observation/eidetic memory only—Gardner Camden is a more serious character than Shawn Spencer).

It's pretty gory, and no one (e.g. children and women) is exempt from threats of harm. There is precious little comic relief, but one such instance actually made me snort.

I stubbornly stayed up way past my bedtime—I just couldn't stop reading. Not only will I welcome sequels, I am open to reading McMahon's first series as well.

If you like police procedurals, thrillers, smart/clever/talented outcast characters (some differently abled), or logic puzzles—and have at least a moderately high gore tolerance—I'd recommend Head Cases for you.

Head Cases is a new type of crime procedural. The FBI has formed a team of misfits to try to solve cold cases. But when one of their previos suspects who they thought was dead suddenly shows up freshly dead, they are put on the case. I loved all of the misfits- honestly what others may see as oddities make them perfect for solving murders. We especially get to see Gardners thought process when even simple tasks require some effort. When it looks like a serial killer is attacking other serial killers, Gardners group is sent all over the country to find clues. Lots of twists and turns plus a pretty heart racing ending. Excellent beginning to what I hope becomes a series!

5 out of 5 Stars!

FBI Agent Gardner Camden is one of the quirky agents in the Patterns and Recognition (PAR) unit, a unit that has a very specific purpose. To solve cases that nobody else can solve. When DNA from a murder victim comes up as a match for a serial killer that was presumed dead, PAR gets into action. This serial killer was supposed to be dead. How did he end up murdered years later? While they are investigating the murder, another body is being discovered. As they try to figure out what is going on, they start to uncover clues that point back to them. The PAR unit will have to work fast to uncover the riddles that the killer has left them. Can they uncover this killer while keeping themselves safe?

WOW! First 5/5-star book of 2025! “Head Cases” by John McMahon was the book I was hoping would set the stage for 2025, and it fulfilled that for me. If you are a fan of criminal TV shows, like Criminal Minds, you will absolutely love this book as much as I did. I felt like I was watching a TV show play out in front of me, with clues and detective work that left you wanting more.

Compared to other mysteries and thrillers, I thought this book was very different but in a great way. For starters, this was a very fast-paced book. More than what I am used to with a real investigation unfolding with a major time element. There was never a dull moment in this novel. While Agent Gardner Camden is trying to figure out who this killer is in his head, they are uncovering new clues and figuring out their next moves. This book had major action throughout, and I promise you, you will not get bored. I thought “Head Cases” was refreshing and felt so real. Yes, I understand they may not solve cases like this as fast as they did and what not, but the flow of the novel felt realistic.

Agent Gardner Camden was a smart character with an interesting backstory. I loved hearing the thought process inside his head and all of his emotions throughout this book. I don’t want to say anything to spoil the book, but his story with his daughter was really sweet and a touch of what his novel needed. I really liked all the characters in this novel and their backstories as well. Everyone in PAR has a story about why they ended up with the unit, and you will discover all of their secrets throughout the story, which adds another element of surprise.

Like I said before, if you are a crime fan or love Criminal Minds, you will LOVE “Head Cases” by John McMahon coming out January 28th, 2025. While reading the acknowledgments, I saw this book is 1 of a 2 part book deal. So, if you read this book and are wanting more, keep an eye out for a sequel coming out!

Thank you to St. Martin’s Press, John McMahon, and Netgalley for a digital ARC of this novel in exchange for my honest review.

Head Cases follows FBI Agent Gardner Camden who is part of PAR unit in the FBI and he was chosen by the director to lead a new case where an old suspect of Gardner's that was supposed to have died a few years ago in a fire has now shown up dead. With the second victim the team sees that a pattern is being established, that the killer they are hunting is hunting serial killers.

Gardner reminded me of Agent Reid from Criminal Minds, who I love so this made the book very appealing to me. For fans of criminal minds this book will definitely be a great read for them. The rest of the team was also very interesting and I hope we see the different relationships blossom next book specially Gardner's and Cassie's. I also hope in the next book we find out more about Shooter as her character was very interesting to me.

PAR usually focus on cold cases so this case was a different take for the team, I hope on the next books we do see the team investigating and solving a cold case.

This was my first book from John McMahon but definitely will not be my last, as this book is the first in hopefully a series about the PAR Unit I cannot wait to see where the next books takes the team.

I gave this book 4.5 stars but rounded for 5 stars as there are no half stars here and the book was closer to 5 stars then to 4.

Thank you to NetGalley and St Martin's Press for this ARC in exchange for an honest review.

"Head Cases" by John McMahon seems like a good thriller for fans of "Criminal Minds."

Unfortunately for me, I was unable to get into the story itself. I made it to 33% but it just wasn't for me. I found myself not caring about the characters or the storyline enough to continue.

Thank you to NetGalley and Minotaur Books for selecting me for this ARC.

**Head Cases** is a gripping psychological thriller featuring FBI Agent Gardner Camden, a brilliant but emotionally distant investigator in the Patterns and Recognition (PAR) unit, which tackles complex cases others have abandoned. Camden’s analytical genius contrasts sharply with his struggles to connect with those around him, including his young daughter, adding depth to his character as he navigates a chilling murder investigation.

The plot centers around a serial killer linked to a brutal murder through DNA evidence, increasing the body count and leading Camden into a psychological game with the killer. The killer’s cryptic clues create a tense cat-and-mouse dynamic that keeps readers engaged.

McMahon skillfully develops the PAR unit as more than just competent agents; their quirky interactions provide comedic and poignant moments that balance the story’s darker themes. Camden's personal journey, particularly his troubled relationship with his daughter, adds emotional weight to the narrative, highlighting the costs of his professional life.

As the investigation unfolds in real time, moving from cold case analysis to active pursuit, tension mounts, amplifying the stakes. **Head Cases** is not only a meticulously crafted whodunit but also a character-driven exploration of human connections and the psychological toll of duty. With sharp writing and unexpected twists, John McMahon offers a thrilling read that will leave crime thriller fans eagerly awaiting his next work.

I enjoyed this book. It gave me Criminal Minds vibes... a team of FBI Agents are put together to solve crimes. I liked the pacing of the story and how the characters got along, as well. I was thinking the serial killer would go one way, and the main character thought so also, and he didn't actually go that way, he twisted it up and went sideways! The book kept my guessing and held my interest.

Amazingly fast read and so interesting that I didn’t want it to end. I sat down and couldn’t put the book down loved the cases and can’t wait for more.