I was thrilled to be approved for this. I immediately dove in, and couldn't put it down. While the beginning was somewhat slow, it didn't take me long to become engrossed with the characters and story. I love the writing style of this author. I am so excited this is a series. I cannot wait for the next book in the series.

While the success of a team of misfit detectives who manage to get the job done in their own ways may not be a new plot line, The characters in HEAD CASES are originals and are very good at their job, well, they are good at this job. Each member of the team has been placed in the PAR Unit after their particular skills landed them in hot water elsewhere. They are originally assigned to apply their pattern recognition skills to cold case reviews. BUT, when a serial killer's body is found, it raises alot of questions to which this team must find the answers.

This is slated as the first book in a new series built around the PAR team. John McMahon has had success in police procedural series, he's the author of the PT Marsh series, an excellent series itself, but has given the cast of the PAR Unit a human touch. Their differences were divisive in the prior jobs, here, their differences make them unique members of a unit ready to prove their abilities as they wreck havoc on the FBI. The personal background of each will be excellent stories in the coming series. 5 stars for Head Cases. Can mcMahon do it again?

I read and listened to an audio book of this story. Each was equally good with the audio adding an extra element to the book. Readers will be happy with either version.

"Head Cases" by John McMahon is an exhilarating start to the PAR (Patterns and Recognition) series, featuring FBI Agent Gardner Camden. Camden is a brilliant yet socially awkward agent, making him an unconventional but fascinating protagonist. The PAR team itself is a group of quirky, “misfit” FBI agents who rely on their analytical prowess to crack complex cases. Their latest challenge? A serial killer targeting other serial killers—a perfect puzzle for this unique team.

The novel provides a deep dive into Camden’s mind and personality. His quirky thoughts—like calculating the millimeters of someone’s Adam’s apple or counting prime numbers to calm himself—add an intriguing layer to the story. While his eccentricities might not appeal to everyone, I found them delightful and relatable, especially if you're a math enthusiast or self-proclaimed nerd (like me!).

The supporting characters shine as well, each contributing a unique skill set to the team. The killer leaves a trail of clues, challenging the team to predict the next victim and uncover whether the killer has an accomplice.

I’m eagerly anticipating the next installment in the series!

Thanks to St. Martin's Press, John McMahon, and NetGalley for providing me with the opportunity to read this ARC and share my honest review.

I have been a long time fan of Criminal Minds and one of my favourite characters on that show was Spencer Reid. So when I started reading Head Cases, I knew I would love this entire book.

Gardner Camden is genius level at solving puzzles and memorising information. He works for a special unit of the FBI called PAR (Patterns and Recognition) The team is full of a lot of screw ups, but they do things that other units cannot do, and that is find clues and put together patterns quickly in order to capture their bad guy.

The entire book is very fast paced, the clues are sprinkled throughout and the puzzle comes together so well by the end of the book. I am very excited to read more about the PAR unit in future books

Thank you to Minotaur Book (St Martin's Press) for providing me with an arc in exchange for my honest review. Head Cases will be available at your local book seller or library on January 28 2025.

4.5 stars

The Patterns and Recognition team (“PAR”) at the FBI, derogatorily referred to as the Head Cases by other FBI agents, is hunting a killer who is slowly murdering other serial killers and leaving clues and riddles for the PAR team to decipher. Their intelligent leader, Gardner Camden, is neurodivergent and often struggles to effectively interact with others. The unit is composed of outcast agents, all misfits who have been assigned there because something they worked on previously went sideways, but each is also incredibly bright. The quirky characters are well crafted, the mystery is a puzzler, and the twists and turns are so engaging. And while the focus is on finding the killer, McMahon does a wonderful job weaving in details about the characters’ personal lives and what makes them tick. This is the start to a new series, and I am already excited for book two. Head Cases is a good fit for people who like intelligent mysteries with unique protagonists.

Thanks to Minotaur Books/Netgalley for the advanced copy of this book for review.

This dad read Head Cases by John McMahon, Book 1 in his new PAR Unit series. This crime thriller revolves around a group of ragtag FBI agents known as the Patterns and Recognition (PAR) Unit. The team consists of agents who are slightly left of center and whose professional careers are hanging by a thread—just like the unit itself. Agent Gardner Camden is the de facto leader, whose personality quirks and neurodivergence make him a straight shooter who often has to course-correct. Although brilliant, he’s juggling his career, being a single parent, and now a serial killer who’s targeting other serial killers. Along with Gardner, the PAR team includes a mathematician, a weapons expert, a computer analyst, and their actual leader, a career agent. Can this team discover the killer’s identity while trying to prevent the next murder?

As a fan of crime fiction, Head Cases checked so many boxes for me. It has a breakneck plot filled with shocks and twists, a cast of characters who are immediately identifiable and relatable, and leaves you begging for more once the final page is read. This is a popcorn thriller, and I mean that as a compliment! McMahon also gets bonus points for mentioning crime fiction royalty, Michael Connelly—an author he obviously respects and is inspired by.

For as relatable as the characters are, I do feel that a few of them fell into tropes that didn’t quite feel authentic. The lead character, Gardner, is neurodivergent, which is treated more as a kooky character trait than a complex part of his identity and it could have been handled with a bit more care. McMahon makes it clear that Gardner’s quirks ultimately serve him and the team, but I wish it was more explicit that his differences are what make him strong. Additionally, one of the PAR agents is a twenty-something Gen Z-er, and her dialogue often felt slightly out of touch—more like what an older generation thinks kids these days talk like. This took me out of the story a little, but it’s a minor criticism that didn’t detract from my overall enjoyment of the book.

If you’re a crime fiction/thriller fan, you will devour Head Cases. McMahon sets up a case that kept me guessing and entertained the entire time, I give it 4/5 and highly recommend it!

A quick and engrossing read. This is a solid cat-and-mouse procedural with a strong cast of characters and a plot that provides complexity without becoming convoluted and confusing. It is complicated enough to hold interest and entertain, without requiring note-taking or a full blown evidence board. The overall vibe is a TV show (think Criminal Minds or NCIS plus Dexter) in book form – easy to consume and satisfying.

But what I liked most about this book is Special Agent Gardner Camden and his fellow investigators in the PAR [Patterns and Recognition] unit. The depiction of Camden is pitch perfect, straight-forward but done with care. He is an analytical genius with an eidetic memory who knows his brain works differently from everyone else. Told from a first-person POV, we get to see and hear that mind working through the facts of the case, the politics of the bureau, and all social situations and interactions. He synthesizes information, analyzes situations, and throws out interesting facts in a business-like, unfiltered manner that he is told is arrogant – but which I found highly entertaining. His personal life has commonality with similar characters in this genre, but there are a couple of really interesting elements adding complexity and tension to his everyday life. Altogether, Gardner Camden is a fascinating character.

The rest of the unit is not as well developed: we get the profiler, the mathematician, the sharp-shooter, and the just-graduated-top-of-his-class rookie whose addition to the team is shrouded in secrecy. This book is the first in a series, so I hope these as-yet largely undrawn characters develop more depth. They are individually, and as a whole, full of potential.

This book is great entertainment and I look forward to the next installment in the series.

Does anyone else find tv procedurals immensely comforting, even when they’re about dark topics? I’m looking at you Criminal Minds, Bones, and Law and Order: SVU. This book went down like a tv procedural, which I mean as a compliment.

This book follows Gardner Camden and his team at the FBI’s PAR (Patterns and Recognition) unit (think Criminal Mind’s BSU) as they hunt down a serial killer who is targeting other killers. It’s fun to follow the team as they put the pieces together, and there are lots of twists and turns. I could not put this book down when I got to the last 25%! We also get insight into Gardner’s personal life, which is something I always appreciate in a procedural: feeling that the main character is human and understanding his motivations.

If you loved Mindhunter by John Douglas (or the tv show based on it), I think you would love this book!

In his author‘s note, McMahon says there’s a second book coming, and I will definitely be picking it up!

Head Cases by John McMahon is an unpredictable thriller about the hunt for a serial killer whose mission is to kill the bad guys. The FBI has a team of investigators that can solve the most difficult cases and (my new favorite character) Camden is chosen to lead. He's great at solving puzzles and piecing together the meaning behind clues but he's not as great at reading social cues or filtering his comments.... which makes him the funniest-without-meaning-to-be, most original character I've come across in forever.

When the suspect contacts Camden and takes his threats to a personal level, the race to find Mad Dog intensifies and it's all FBI hands on deck. The fact that Camden isn't sure who not to trust makes things even harder because the rookie on his team has questionable credentials, the head of the FBI has made questionable decisions, and Camden's mind is working overtime to figure it all out.

I'm beyond grateful to NetGalley for the ARC of Head Cases and even more grateful that this is the first book in the series by John McMahon. I can't wait to see what Camden and his brilliant mind take on next....

When I delved into John McMahon’s Head Cases, I was immediately drawn into a labyrinthine narrative that masterfully intertwines psychological depth with relentless suspense. 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.

The narrative gains momentum when DNA evidence links a recent murder to Ross Tignon, a serial killer presumed dead for years. As the body count rises, it becomes evident that the perpetrator is not only targeting serial killers but is also orchestrating a macabre game, leaving behind cryptic clues specifically designed to challenge Camden’s intellect. This cat-and-mouse dynamic propels the story forward, with each revelation intensifying the stakes.

The novel’s pacing is meticulously calibrated, with McMahon deftly alternating between high-octane action sequences and introspective moments that delve into the psychological toll of pursuing a cunning adversary. The tension is palpable, and the plot is replete with unexpected twists that kept me continually reassessing my theories about the killer’s identity.

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

I requested “Head Cases” because I’ve always been a big Criminal Minds Spencer Reid fan. And that’s basically what you get with “Head Cases” by John McMahon. Gardner Camden is the socially awkward FBI agent with an eidetic memory who spits out random facts as he struggle with social interactions like Spencer Reid . Instead of the BAU you have the PAR. The PAR however normally investigates cold cases but during the story they are forced into the field as a killer they thought had died years before turns up dead.
I normally just read romance but this book caught my eye and I’m glad it did. The pacing of the story was great. I never got bored. The plot kept me turning the page to find out what happened next. This fulfilled my Criminal Minds/Bones cravings in book form.

Head Cases features a specialized unit within the FBI who are called in when an investigation hits a dead end. The Patterns and Recognition unit (PAR) is comprised of a small group of agents who have unique abilities to solve puzzles and find new threads to pursue to solve stalled cases. Other agents often derogatorily refer to PAR as Head Cases. It’s unusual for the PAR agents to work in the field, but when a serial killer who was declared dead years ago is identified as the victim in a recent murder, the unit is sent to investigate. Before their investigation has really even begun, there’s another murder and they must quickly put all the clues together to stop the vigilante. This is a thoroughly entertaining story that has an interesting cast of characters and a storyline that will keep you engaged until the final page is turned. If you enjoy FBI/police procedurals or programs like Criminal Minds, NCIS, CSI, or Bones, you’ll enjoy reading this book.

This book was EXCELLENT! I absolutely love FBI & serial killer plot & this one was great. I thought the plot was fast paced & unique. I enjoyed the twists! & I really loved meeting the characters…the Head Cases! I could see this being a great movie or even series! I look forward to more books in this series!

This book is about a case that is being handled by the FBI Unit known as PAR. Each of the individuals in the unit has made some sort of error. This is one of the 1st times they have been in the field since they usually only deal with files for Closed Cases. This instance they are working on a case where the victim is someone who supposed several years earlier. The leader on this case is being led by Gardner Camden, who was involved with a case where the victim was supposedly burned alive.

The victim of this case was a serial killer that the FBI was closing in on when his body was found burnt many years earlier. There is not a lot of evidence for this and before they really get involved, Gerald receives another call advising him of a body that was discovered in New Mexico of another serial killer who had just be released from prison. In a short while when Gerald went to view the autopsy of the 1st victim, he received a call which was from the killer. This call referenced another killing in Calif. that was similar

Gerald figured out that the killer was obtaining information from an FBI source. He finally nailed it down to one individual who had logged into specific files. This individual was highly placed and immediately cleared. With the login information, they tried to lay a trap to narrow the location where the killer was at. A specific location was identified and a team was sent to arrest this person. Gerald made arrangements to be on site.

Gerald finally got the killer angry and Gerald's family was threatened. He made arrangements to keep his daughter safe but forgot about his mother. The mother was attacked an as a result of Gerald's action, he was suspended. Gerald convinced Frank to help him out. Gerald came up with who the killer was and Frank went to capture him while Gerald was to go home. Gerald still was working out how to locate the killer. The location was identified and Frank went to make the arrest. Things did not go well.

To learn who the killer was, what his reason for killing the people was, what event forced the killer to seek revenge and how it all worked out in the end, then you need to read this book.

Head Cases introduces us to a specialized FBI team (PAR) that is called in on cases that have stalled, for their expertise in patterns, mathematics and data. We are introduced to one of the agents, Gardner Camden, who is great in his position, but like the others on the team, were relegated to this behind-the-scenes department due to missteps in is his career. Camden is a likeable character who is aware of his flaws, making him transparent and human to the reader.

The PAR team is called to a case where a serial killer is found murdered. The twist is this serial killer supposedly died in a fire years ago and was an old case of Camden. Soon, other murderers are murdered, and the team must find out who is behind the crimes. What makes the case even more intriguing are the politics inside the FBI, when it is obvious that the killer knows things that are only contained in the FBI case files.

I enjoyed this debut series and the characters that were developed in the book. There was a good pace as the clues led to the killer and also revealed other secrets and agendas in the FBI leadership. I recommend this book and look forward to future installments.

Thanks NetGalley and Minotaur Books for the advanced copy

This book was so good! It felt very cinematic. The story was twisty and left you questioning everyone in it. I enjoyed the references to the past cases, the peaks into the lives of the main character AND to know the life was not perfect. It was a fast book that kept me wanting more! Highly highly recommend.

Thank you to NetGalley, Minotaur Books and the author for the opportunity to read an ARC of Head Cases, scheduled for release on January 28, 2025. Discovering a "new to me" author is fun; discovering a great writer is bliss. I discovered a great writer while reading Head Cases by John McMahon. Head Cases is the first, in what I hope will be a long running series, featuring Gardner Camden and the FBI Patterns and Recognitions Unit. The Unit in this story is comprised of Frank Roberts, Unit director, Cassie Pardo, a mathematician, Joanne "Shooter" Harris, a former Olympic sharpshooter, Richie Brancato, a recent grad and number one in his class at Quantico and Gardner Camden, a man with an eidetic memory. The unit was often considered as the nerds, head cases, socially inept agents; thus they worked research, not actively in the field. Another point of interest, each of the members had something in their professional past that diminished their light in the eyes of FBI leadership, with the exception of Richie Brancato, yet his personnel file was sealed.. It was certainly a surprise when Gardner Camden and Cassie Pardo were called to Texas to investigate a murder. Could the victim be Ross Tignon, a series killer the FBI believed had been killed years before in a house fire? While completing that assignment, they are called to New Mexico to investigate the identity of another viciously murdered seriel killer, Barry Fisher. Could it be possible that a seriel killer was murdering seriel killers? Head Cases is a finely crafted thriller with such a well developed plot and characters that I couldn't put it down. The Unit members came alive on the pages as well as the support characters including Gardner's mom, daughter and the national FBI director. Head Cases also explores the politics, the pride and the integrity that drives some agents and former agents as well as illustrating the pursuit of excellence at all costs by some. I am anxiously looking forward to the second book in this series, hopefully in 2026 according to the author. Kudos to John McMahon for this new series; I highly recommend Head Cases. This review reflects my honest opinion. 4.5 stars.

“Head Cases” by John McMahon is a suspense thriller. It’s the first book in the “PAR Unit” series which is a group of secretive FBI agents hunting a serial killer that was thought dead. This is an exciting new series with enjoyable characters.

ɴᴇᴛɢᴀʟʟᴇʏ ʀᴇᴠɪᴇᴡ || HEAD CASES [thank you to @minotaur_books and @netgalley for my #gifted copy!]

Title: Head Cases
Author: John McMahon
Genre: Suspense, Thriller
Format: Digital
Star Rating: ★ ★ ★ ☆ ☆

ꜱᴜᴍᴍᴀʀʏ:
FBI Agent Gardner Camden and his team of brilliant misfits must crack a killer’s deadly riddles—but as the murderer closes in on their personal lives, the stakes become terrifyingly personal.

ᴍʏ ᴛʜᴏᴜɢʜᴛꜱ:
This book was a wild ride - if not, ultimately, like watching an episode of tv that isn’t my favorite but gets the job done.

If there’s one thing that I like about Spencer Reid, it’s that he generally walks you through how his brain comes to a conclusion - & that was missing here. 🤷🏻‍♀️

I always prefer it when I’m able to try to follow the dots myself, rather than having the author tell me what the dots are. So that was a miss for me. But this was a quick, easy read if you’re looking for an escape!

ʀᴇᴀᴅ ɪꜰ ʏᴏᴜ ʟɪᴋᴇ:
Criminal Minds
Police Procedurals
Mindhunter
Zodiac
Fast-Paced Mysteries

ᴅᴇᴛᴀɪʟꜱ:
GR: 4.25 ⭐️
# of Pages: 352
Pub Date: January 28, 2025

3.7 Stars
One Liner: Entertaining but don’t think too much about it

FBI Agent Gardner Camden is an analytical genius and one of the four super-talented agents at the PAR (Patterns and Recognition) unit. Of course, this comes at the cost of human emotions, something he fails to achieve even with his seven-year-old daughter.
When the DNA of a new victim reveals he was recorded dead seven years ago, Gardner is called to investigate the case (along with his team). A second death occurs, starting a pattern they need to break to stop the killer from committing more murders.
However, things are complicated, and the killer knows a lot more about PAR and its members than they do. Can Gardner and his team solve it before their lives are in danger?
The story comes in Gardner’s first-person POV.

My Thoughts:
The premise screams high competence coupled with wonder kid-type talent which made me want to read the book. The 4-star reviews by friends sealed my decision. Despite the flaws, I don’t regret reading it. In fact, I want the series to be longer than two books (with the hope that the flaws get addressed).
The initial 30% is slow despite starting with the murder. We also get details about the team members and teeny backstories. The foundation is laid, so makes sense that the pacing dips. The second half was pretty fast for me. It sustained the momentum with reveals and twists. Is some of it a bit too convenient? Yeah, it is but still fun.
Each member of the team has a distinct ability and a reason for being in PAR, and the reasons aren’t always good. While this adds some layers to the characters, there isn’t enough to turn them into strong personalities. Gardner gets better profiling since he is the MC and the voice of the book. His personal life is rather interesting, something similar yet different to what we tend to see in the genre.
The police procedural part was cool, especially since we have these competent fellas working on the same. They are still human - make mistakes, miss clues, and even go in circles. But hey, you can notice they are good at what they do.
The MC likes to share random insights and facts. Since this doesn’t get excessive, I liked how it added to his personality. Don’t bother about connecting with him or others. It’s not likely that we will. Think of it as a TV show (Criminal Minds maybe) in book form.
The MC’s mother has a short yet important role. I hope she will be featured in the next book too. His daughter is certainly interesting but we don’t see enough to get an idea. Of course, she’s just a sweet seven-year-old.
Naturally, there are office politics but it doesn’t overpower the central plot. It is woven into the mystery and provides a smooth landing for the ending and maybe a lead for the next book.

To summarize, Head Cases is an entertaining novel if you like FBI-style police procedurals with highly talented characters. While it has a few issues, there’s no denying that I enjoyed the book and look forward to the next one.
My thanks to Steve Erickson, NetGalley, and St. Martin’s (Minotaur Books), for eARC. This review is voluntary and contains my honest opinion about the book.