This novel introduces us to the FBI’s Patterns and Recognition (PAR) unit, a team of uniquely skilled agents tasked with deciphering the most perplexing cases.

At the forefront is Special Agent Gardner Camden, an analytical genius whose prowess in solving intricate puzzles is juxtaposed with his challenges in navigating human relationships, including those with his colleagues and his cherished seven-year-old daughter, Camila. This dichotomy adds a compelling layer to his character, making him both formidable and relatable. McMahon’s portrayal of the PAR unit is both nuanced and engaging. The ensemble, comprising a mathematician, a weapons expert, a computer analyst, and their seasoned leader, operates with a synergy that underscores their collective brilliance while highlighting individual idiosyncrasies. Head Cases is a compelling addition to the crime thriller genre, showcasing John McMahon’s talent for crafting a narrative that is as intellectually stimulating as it is thrilling. The interplay between the enigmatic protagonist and his elusive quarry creates a dynamic that is both engaging and thought-provoking.

Thanks to the publisher and Netgalley for the ALC in exchange for an honest review.

"Our job is to identify peculiarities in cases that have stalled. To solve puzzles and highlight new theories."

An FBI team hunting a serial killer? Yes. I’m ALL in! I love group dynamics with each member bringing their unique skills to the table and HEAD CASES nailed it! Rather than focusing on profiling, this team excels at pattern recognition. No one more so than the team’s quirky yet highly intelligent leader, Gardner Camden. Told entirely from his point of view, John McMahon beautifully and accurately showcases a neurodivergent character that I couldn’t have loved more. He’s diligent, honest and holds a myriad of miscellaneous facts in his head, which he thinks about at random intervals that had me chuckling!

The investigation progressed at a steady pace that increased in tension and sped up to the point where I couldn’t put it down! I became ENTIRELY invested in the characters and particularly attached to Gardner who is resolute in his beliefs of right and wrong and tries his best to navigate relationships based on advice he calls to mind from his beloved mother.

Will Damron is a SUPERB narrator and is now one of my favorites! Not ONE single character sounded the same with voices so distinct (some with accents), that I knew who was speaking immediately. His inflection and delivery of the killer was simultaneously chilling and charismatic. Yet as Gardner’s mother, his tone had a sweet and maternal calming effect. You simply MUST grab the audiobook along with the physical book for the complete experience. One of THE. BEST. audio productions I’ve listened to!

HEAD CASES hit ALL the marks with a diabolical antagonist, a fully fleshed out ensemble cast and an investigation that barreled full steam ahead to an action packed conclusion! I couldn’t get enough of this intense crime thriller with heart and will be first in line for the next installment. In fact, I’m ready for book two. NOW!
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FAVORITE QUOTES:

"He reached out his hand. I stared at it. Over two hundred bacteria thrive on each square inch of our palms. 'Gardner Camden,' I said, shaking. I'm not OCD. I just know things like this."

"I remembered a piece of advice that my mother taught me years ago. To add bits of information at the starts of conversations. To be perceived as more likable. Emotional."

"I nodded, thinking about the two men. They had operated in different decades and in different states. Ages apart, really.
But even though they were unrelated to each other, there was a pattern.
A serial killer was murdering serial killers."
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Potential spoiler content warnings below.


































⚠️Content Warnings: language, dementia, poisoning, mild gore, violence, gun violence, Mention of: gruesome crimes

This was a great cat and mouse thriller. I loved the main character and how his differences were highlighted. I loved the “Criminal Minds” ish way this team worked together. I listened to this as I drove on a long car trip and it kept my attention the whole time. It was intense! Can’t wait to see the next adventure for the PAR team!

This had all the Criminal Minds vibes and I really enjoyed the suspense and the smart MC. I couldn't stop listening once I started, I thought it was great on audio with the way Will Damron brought Camden to life.

This may stay my favorite book of 2025! I listened to it and immediately preordered it for my dad - because my husband said I needed to talk about it with someone who has read it …not just him. This book is amazing - love the set up, the suspense, the writing. I couldn’t stop listening. Goodreads has this marked as book 1, I really hope this is going to be a series!!!

I loved this one and can’t wait for the next in the series.

Par is an elite group in the FBI. The members are incredibly smart and a bit socially awkward. This task force is assigned to a new case. The killer is chasing down and killing serial killers.

If you like a smart police procedural with Criminal Minds vibes you will love this new series.

Thank you netgalley for a copy of this book!

FBI Agent Gardner Camden is in a unit called PAR (Patterns and Recognition). The agents in this unit all have past issues with other jobs that have landed them there, and they are known by others as the head cases. Gardner especially has trouble with nuance and reading the room sometimes; it’s even caused problems in his own family. When PAR is assigned the case a murdered man who they believed to be already dead, they uncover a killer killing serial killers. This book is told through Gardner’s perspective, but readers get some insight into the whole cast of agents. The audiobook narrator does a good job of bringing their personalities to life, and he makes Gardner a sympathetic and intriguing character. This will be a series to watch out for; readers will be eagerly awaiting the next installment after the ending of this one.

I listened to an advanced audiobook copy of this title from NetGalley. All thoughts and opinions are my own.

Head Cases is a super-strong start to an all new Police Procedural Mystery series, following an elite, yet obscure, unit in the FBI called PAR (Patterns and Recognition). I learned about this book through good ole' fashioned word of mouth, and I could tell from what my friends were saying that this would align with my taste. Happily, it certainly did.

Our MC is FBI Agent Gardner Camden. He's undoubtedly an analytical genius, but unfortunately, the people-side of his analysis tend to be lacking. He's a puzzle genius, yet a mediocre people person. Nevertheless, along with the rest of the team, each bringing their own special set of skills to the table, they're a true force to be reckoned with.

The case in question involves a murder victim whose DNA links to a serial killer long-presumed dead. A 2nd-victim establishes a pattern, and the killer seems to be leaving behind clues and riddles especially created for Gardner. The team flies into action and the rest of the story is a whirlwind of cat-and-mouse suspense as Gardner gets closer-and-closer to catching the killer.

I listened to the audiobook for this one and found it to be so gripping. I highly recommend that format should you have access to it. I felt the narrator became Agent Gardner for me. It was completely believable. I loved the quirky team as well. They each have their own strengths and weaknesses, working well together to get the outcome they all desired. I love when strong teams are shown on page, versus teams full of drama and strife.

I would HIGHLY recommend this to fans of Criminal Minds. I was totally picturing Matthew Grey Gubler and Shemar Moore the whole time, which obviously is not a bad thing...

I'm not sure what the long-term plan is for this series, but the possibilities are endless. I'd definitely be down for joining this team on a lot more cases. Thank you to the publisher, Macmillan Audio, for providing me with a copy to read and review. I cannot wait for more PAR Unit!!

4.5 stars 🌟

Everyone is comparing this novel to shows like Criminal Minds and I can totally see why. It totally brings back that nostalgia of early episodes and particular characters (Spencer/Gideon?). The premise/storylines of the FBI vs. Serial killers is always such a hit for audiences, and Head Cases is a prime example. I enjoyed the plot and the care of detail put into introducing main characters and their backstories. I'm interested to see where the series goes from here. I didn't love knowing that it was the first in a series, though, as that spoils part of this book's ending. Is PAR going to disband?? Would be hard to do considering this is PAR #1, lol.

Reading challenge category - 2024 Hoffbensen: Kellie - furthering education/career

Thanks to #NetGalley for the ARC copy of this book.

Agent Gardner Camden (not a fan of this name choice Mr. McMahon) is a member of the Pattern and Recognition Unit (PAR) with the FBI. Camden has a different personality and perspective, making him uniquely qualified to lead this unit. When serial killers are being targeted by a serial killer (a la Dexter Morgan), Camden's team finds clues that other FBI agents have missed. It's up to them to solve this case before one of their own is hurt or worse.

Very reminiscent of other procedural crime - CSI, Dexter, Will Trent, but well written!

My newest obsession! This was such an addicting listen. I absolutely loved FBI Agent Gardner Camden. His story is fascinating, and the way the author weaves his analytical genius into the plot is so well done. Camden is part of a PAR unit which investigates patterns and recognitions to solve unsolved cases. He finds himself smack dab in the middle of a case where he thought the suspect had died, but not everything is as it seems.
A great mystery and suspense listen that had me on the edge of my seat more than once. Will Damron’s narration is solid, with tones and inflections that fit Camden perfectly. Great narration that breathes life into the characters.. If you love police procedurals, Criminal Minds or any FBI thrillers, this is definitely one to add to your list!

I really liked this book and the story. I really liked the description and the portrayal of the characters. The way the main character was portrayed made me think that he may have a spectrum disorder but his brain, much like neurodivergent individuals is amazing. That's just my take as I don't think the book mentioned the specifics. I am looking forward to more. I'm really hoping this is a series. I highly recommend this book especially for those who love crime stories.

Head Cases
by John McMahon
Narrated by Will Damron
"Head Cases follows an enigmatic group of FBI agents as they hunt down a murderer seeking his own justice in this electrifying—and commercial—series debut. FBI Agent Gardner Camden is an analytical genius with an affinity for puzzles. He also has a blind spot on the human side of investigations, a blindness that sometimes even includes people in his own life, like his beloved seven-year-old daughter Camila. Gardner and his squad of brilliant yet quirky agents make up the Patterns and Recognition (PAR) unit, the FBI’s hidden edge, brought in for cases that no one else can solve. When DNA links a murder victim to a serial killer long presumed dead, the team springs into action. A second victim establishes a pattern, and the murderer begins leaving a trail of clues and riddles especially for Gardner. And while the PAR team is usually relegated to working cold cases from behind a desk, the investigation puts them on the road and into the public eye, following in the footsteps of a killer."
As always, my reviews are of the audio version of this book. As a rule, I listen at 70% speed or less as this makes it easier to hear details without needing to rewind as often. If things get tedious, I generally speed up.
Present in all of my reviews will be notes marked by an asterisk. These are pretty much just random thoughts I have, ignore them if they are annoying. I tend to think out loud...or in writing.
**New (to me) author alert!** This means I'mma be a little skeptical from the get go...
Well, right off I had a concern. One of the first sentences was "why kill someone who was already presumed dead?" I found this inane. Well, duh, bc they aren't IN FACT dead??? This gave me a bad feeling about the rest of the book.
BUT WAIT! All is not lost!
Let's get on with the REST of the story...
Firstly, our protagonist, Gardner Camden (gotta say, never have I encountered this first name), is perhaps meant to be ... on the spectrum? At the beginning, this is not made clear.
Maybe that is how the self absorption in the first few chapters is explained.
Camden is an agent in an FBI unit called PAR, made up of some very intriguing characters.
*Note: Needs a bit of editing.
Ex "each letter in perfectly formed letters". An awkward way to say "each letter perfectly formed".
*Note: there, once again, is a horrible southern US accent. Pet peeve. Not too irritating as it is not used often.
Just a warning:
Major ICK factor beginning in CH 7.
It doesn't seem to be ENTIRELY for shock value, but imo, the dog (NOT a spoiler) could have been left out as the detail added nothing at all to the plot and I prefer animals in books be enjoyable.
**NOTE: the dog DOES NOT DIE nor is it harmed in any way! This would've been an automatic deal breaker for me!
*Note: Is anyone else annoyed that people on cell phones are always hearing dial tones in books and shows?
Happily, the story became much more interesting after about 25-30%. Before this, there was a noticeable drag.
Camden is definitely meant to be ots (what I'm not supposed to call Asperger's anymore). Now that I consider it, I don't think he is ever referred to as anything but "different". I presume this is the author's way of avoiding labels, however, as I have a son who is ots as well, calling a child "different" is NOT good when most children don't desire standing out from their peers, especially in early childhood. We found that explaining his diagnosis helped the other kids understand a bit better; calling him "different" only caused his classmates to ask and speculate HOW he was different, often erroneously. My son's mentality is also somewhat similar to Camden's, so I found this interesting and his behavior pretty accurate, thankfully. There were few, if any, stereotypes involved.
One slightly annoying aspect (one of few) is that toward the end, there's some very looooong stretching to put the most obscure clues together. Some of it is sort of ridiculous.
As often happens, I'm a bit disappointed with the drop in common sense Camden exercises in the last several chapters, but you can't have it all. I feel like some of the drama at the end is word carbs.
Overall, I enjoyed it way more than I thought I would from the iffy beginning and I am definitely interested to see if there is another book coming. The ending is open to a continuance of the group's adventures.
I love being proved wrong!

I requested this book after reading an excerpt of it a little bit ago. There is always a special section of the FBI that does what no other department can do. Do you think they all feel like that? I bet they do. I can't imagine being in that one FBI office that just KNEW you were the worst of the best. You were the ones that didn't quite rise to expectations. The ones that the other agents felt bad for. It seems like there isn't much reason for you to be "special" but you were already there and you had your clearance and badge, so....

But this isn't that group. This is the one that is good at their job. This is the one with the odd and brilliant member that holds them all together. And it was a good story. Lot's of action. No easy answers or completely out there twist endings. This is just my way of saying that this was familiar in that way that basically all books about elite groups in already elite crime fighting agencies. I feel like it is just short of making itself distinct. Most first book in a series are. They want to feel familiar. Then you see the distinctions. I will read the second book that is sure to come. There is the hint of relationships in need of being explored and backstories to learn.

Head Cases was engaging from the very beginning!! The audiobook was well paced and the narration was great, hooking me from start to finish. This book is perfect for those that enjoy shows like Criminal Minds or Law & Order. The story follows a team of FBI agents, in the midst of their search for a serial killer that kills serial killers. As each victim falls prey to the antagonist in this story, these agents try to profile their killer before he can strike again. Meanwhile, the killer is playing a cat & mouse game by calling the agents, taunting them as he is confident he will never be caught. Perfect for fans of crime fiction and I plan on exploring more titles by this author.

Thank you Macmillan Audio for providing this book for review consideration via NetGalley. All opinions are my own.

John McMahon has created a thriller peppered with puzzles that will keep your mind searching for the next clue and action that keeps the reader ready for more. Patterns and Recognition Unit is an FBI unit normally assigned to cold cases. Camden Gardner is a genius who solves puzzles. His eidetic memory helps him catch the killers, but he lacks social skills. He and a group of uniquely talented agents are assigned to a new case when a serial killer who supposedly died in a fire seven years ago, has just been murdered. The plot is full of twists and the characters are interesting, making for a compelling story. I can't wait to read the planned sequel.

I alternated between the ebook and the audiobook and I enjoyed the narration by Will Damron immensely. His acting was versatile and the voices were varied enough to differentiate between the characters. He softened his voice for the female characters without going into an unnatural falsetto that could be distracting or annoying. I will definately be on the lookout for other audiobooks with this talented actor. I received access to both the ebook and the audiobook from the publisher, but this review is voluntary. I can honestly say that no matter which format you prefer, this is a new series to watch out for.

My husband recently asked me if we could read the same book and discuss it... hard to keep the romance alive with 3 kids during cold and flu season. I obviously said yes! He is not as big of a reader as I am, so I wanted to find something that I knew he would like - and this sounded like it would be a good fit! I have to say, I was so pleasantly surprised by this book. I had an audio of this from Netgalley and I flew through it. I often find FBI thrillers to be predictable and so unrealistic. This one moved quickly, the storyline was addicting and the characters were all really well developed. I was on my toes from page one, the twists and turns were great and it was very action packed. Anyone interested in serial killers, FBI, and a serial killer seeking revenge on other killers.

Thank you Netgalley for my advanced reader copy.

Head Cases by John McMahon is a captivating and fast-paced debut that introduces readers to an exceptional FBI unit tasked with solving the unsolvable. The story follows Gardner Camden, a brilliant yet socially awkward agent in the Patterns and Recognition (PAR) unit, a team of FBI specialists who tackle the most perplexing cold cases. When DNA links a recent murder to a long-dead serial killer, Camden and his team are thrust into a high-stakes investigation that quickly spirals into a deadly game of cat and mouse.

What sets Head Cases apart is its unique cast of characters, each with their own set of quirks and specialties. From a mathematician to a weapons expert, the diverse team works in tandem, using their collective expertise to crack the case, while Gardner’s personal blind spots add an intriguing layer of complexity to the investigation. The killer, however, is always one step ahead, leaving behind a trail of puzzles designed specifically for Gardner. As the investigation unfolds, the tension rises, and it becomes clear that the team is not just hunting down a murderer—they are also racing against time to protect their own families from the killer’s growing obsession with them.

With its sharp writing, intricate plot, and engaging ensemble cast, Head Cases keeps the reader hooked from start to finish. McMahon masterfully balances thrilling action with psychological depth, offering a story that’s as intellectually stimulating as it is suspenseful. For fans of twisty crime thrillers with a touch of genius, Head Cases is a must-read.

Head Cases feels like a perfect blend of some of the best crime and procedural TV shows. It reminded me of Scorpion, with its team of uniquely skilled misfits trying to keep their funding and avoid getting shut down. It also had the charm and wit of The Mentalist, particularly with the budding romance subplot that gave me early Jane and Lisbon vibes. And, of course, there’s a Criminal Minds feel, with a specialized team solving complex cases while navigating their own interpersonal dynamics.

This book does a great job of balancing character development with the procedural elements. We’re introduced to a team where each person has their own distinct personality, and we get just enough backstory to keep us intrigued without being overwhelmed. For readers who love longer detective series, this sets up a promising foundation. I also liked how the book immediately shows the dangers of the job and how they impact the characters' personal lives. It gives the story an emotional depth and foreshadows the kind of long-term stakes we’ll likely see in future installments. I already get the feeling that one day, a past case will come back to haunt them, which is always a great setup for a crime series.

Overall, this was a solid, engaging read. It wasn’t mind-blowing, but it felt like watching a two-hour special of my favorite crime, cat-and-mouse serial killer shows. Thanks to Macmillan Audio and NetGalley for this ALC—the narration was fantastic! The narrator did an amazing job giving each character a distinct voice, which made the story even more immersive. If this does turn into a series, I’ll definitely be keeping an eye on it.

FBI Agent Gardner Camden along with a group of quirky and sometimes outcast agent make up the Patterns and Recognition (PAR) unit. When a serial killer, long thought to already be dead, is found dead quickly followed by another serial killer, Agent Camden and PAR are brought in to try and solve the crime. After quickly finding a few clues that were left, Camden and his fellow agents race to beat the clock and the possible closure of their unit, while Camden also needs to make sure his family is kept safe. Head Cases was a heart pounding, crime focused thriller with excellent, fully fleshed out characters. Hoping Gardner and PAR will be returning for many more books to come!