A good first outing in a new series from John McMahon, featuring an FBI agent named Gardner Camden who is 'somewhere on the spectrum' and is part of a team nicknamed Head Cases because, while they have 'good heads for cases,' they are also oddballs in different ways.

Gardner takes the lead on their current case and it's a weird one--it appears someone is targeting serial killers. The temptation is to say 'Have at it!' but of course they need to find and stop this killer and boring them to justice.

Very interesting characters, especially Gardener who is telling this story in first person. It's fascinating to see how his mind works and puts information together. He is so smart but often so clueless about human interactions.

Many thanks to the author and publisher for providing me with an arc of this new suspense thriller. This was my first taste of McMahon's books and I look forward to reading more. My review is voluntary and the opinions expressed are my own.

“Head Cases”, the first novel in the new PAR Unit series by author John McMahon, follows FBI Agent Gardner Camden. Gardner is a member of a special team within the FBI called PAR, Patterns and Recognition. PAR basically consists of the freaks and geeks of the FBI who are especially skilled but also more than a little anti-social (even neurodivergent).

One day a wild case comes across their desks – the murder of a serial killer who they thought died a long time ago amidst their investigation of him. But that’s just the first in a string of similar crimes and their search for the killer (or killers?) will take the team all around the country.

This is the kind of book that grips you from the first page and will have you stay up reading till 2 AM just to see what happens next. The pacing of the novel lends itself perfectly to TV so I was thrilled to hear the TV rights have already been sold.

This book is perfect for fans of TJ Newman, “Criminal Minds”; or those who are fascinated with serial killers and mile-a-minute crime procedurals.

It isn’t a read that I’ll be thinking about for years to come but it so much fun, I anticipate it will be *the* mystery/suspense/thriller of 2025, and I can’t wait for the next book in the series and eventually the TV adaptation!

3.5 rounded up. Thanks to NetGalley and the publisher for an ARC in exchange for my honest review. I enjoyed this first book in a series about a section of outcasts within the FBI. It was somewhat reminiscent of the team from Slow Horses and I look forward to future installments.

This is a compelling new FBI/police procedural series for fans of Criminal Minds, solving puzzles, and unraveling mysteries. The PAR unit of the FBI, also known as the Head Cases, are made up of a brainy, nerdy talented crew of misfits who use their strengths to solve cold cases. I loved following along and trying to solve the case along with them. This novel focuses on catching a killer who is targeting serial killers - a perfect, compelling plot (who doesn’t love a great serial killer thriller!) The main narrator is slightly neurodivergent- he has a sharp mind but is less adept at social interactions. Because he is the one to introduce us to the other characters in the book, I did find the character descriptions to be repetitive and one dimensional (we get in depth descriptions of each characters clothes and what they are eating multiple times in the book). Other than that, I really enjoyed this one and look forward to reading the next in this series and getting to know these characters more.

Thank you to NetGalley and St Martin’s Press for an advanced reader copy in exchange for my honest review.

Wow! Head Cases was one of the best police procedural thrillers I have read in a long time. I truly enjoyed taking the ride with the special FBI unit assigned to catching a serial killer. This book took many twists and turns and I stayed up way too late to finish it! I highly recommend it to all readers who enjoy the show Criminal Minds or books with puzzles.

Thank you NetGalley and Minotaur Books for sending this book for review consideration. All opinions are my own.

Gardner Camden is an FBI agent in the PAR unit (Patterns and Recognition). He sees patterns in crimes that others do not see. When he is called in to find someone that is killing serial killers, he must work with his team to figure out who is leaking information and see the patterns in the killings before more people die.

I really liked this FBI/ police procedural. It was fast paced and intricate but not so much that it was twisty. I liked the characters a lot and thought it was a good balance of plot and character building. This is clearly going to be a series a will definitely continue reading it.

Thank you to Netgalley for the advance copy for review.

I think I have a new favourite series and I honestly can’t wait until book 2 whenever that may be because this one doesn’t even come out until the end of the month 🤦‍♀️
If you are a fan of Criminal Minds ( or similar series) you will love this one ! Hard to put down suspense & action ; quirky but lovable FBI agents and a serial killer … well more like a few!

My rating 4.5 ⭐️

John McMahon’s Head Cases is a gripping FBI thriller that will keep readers hooked from start to finish. With its complex characters, a brilliantly twisted killer, and a narrative that maintains tension throughout, this book is a standout in the crime thriller genre.

The story centers on FBI Agent Camden, whose unique perspective and emotional detachment make him an unconventional protagonist. While his personality might not resonate with every reader, it’s precisely this trait that makes him compelling. His ability to think differently becomes a vital asset in the pursuit of a diabolical killer, and McMahon expertly weaves this into the narrative. Camden’s struggles with feeling “different” add a layer of depth to the story, making him more than just a typical crime-fighting hero.

The writing style is sharp and immersive, with McMahon skillfully building suspense and delivering unexpected twists. The antagonist is chillingly well-crafted, keeping the FBI—and readers—on edge throughout. The pacing is spot-on, with each chapter driving the plot forward without feeling rushed.

For those who enjoy audiobooks, the Audible version comes highly recommended. The narration enhances the story, drawing listeners deeper into the world McMahon has created.

In summary, Head Cases is a masterful blend of psychological depth, thrilling action, and a cat-and-mouse game that will leave readers guessing until the end. Highly recommended for fans of crime thrillers who appreciate a unique protagonist and a plot that keeps them on their toes.

This gripping series opener follows a team of exceptionally intelligent but quirky FBI agents in the Patterns and Recognition (PAR) unit. Told from the perspective of Agent Gardner Camden, the story centers on a serial murder investigation that begins with the unexpected reappearance of a serial killer presumed dead for years. As the agents become entangled in the killer's intricate web of clues and puzzles, the future of their unit—and their careers—hangs in the balance as they race against time to catch the elusive murderer.

The book is a compelling read, masterfully written with engaging, well-developed characters and a perfectly paced narrative. The tension steadily builds, culminating in a thrilling conclusion. The author skillfully plants subtle clues throughout the story, keeping readers on their toes and constantly questioning which details are important. Camden, the protagonist, takes note of numerous intricate details, inviting readers to join him in piecing together the mystery. The intriguing premise sets the stage for future installments, with a sequel already scheduled for release in 2026.

A series launch focused on a group of quirky but extremely intelligent FBI agents in the Patterns and Recognition unit (PAR). Narrated from the perspective of Agent Gardner Camden, the book follows an serial murder investigation starting with the death of a serial killer who was presumed dead years ago. The agents quickly get drawn into the killer's web of clues and puzzles, and the future of their unit (and their jobs) depends on catching the killer in time.

This was an excellent book. The book was well written, the characters were all interesting and well-developed, and the pacing was perfect--steady and really picked up at the end when everything comes to its conclusion. The author drops subtle clues about the case, yet still keeps you guessing the entire time. The main character constantly notes lots of details so you as a reader are trying, along with the characters, to suss out what's important and what's not. The premise was intriguing and the book is set up perfectly for a sequel (coming in 2026).

Highly recommended for fans of Criminal Minds.

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

The Patterns and Recognition (PAR) Unit of the FBI is headed by Gardner Camden, whose unique way of looking at the world helps him to solve the hardest riddles and puzzles. Cassie Pardo is the numbers and statistics expert, Joanne "Shooter" Harris knows everything about weapons, and new agent Richie Brancato is a wild card. The PAR Unit is where agents go for their careers to die. Even other agents refer to PAR as the freaks, misfits, and weirdos. They've been called in on this case to prove their worth to the FBI. Can they find the vigilante taking out serial killers? Or will they fail and have the unit disbanded?

This was slow to start, I wasn't sure I was going to finish it. Once the mystery was set up and they started trying to track the killer, the pace sped up. I thought I knew early on what the twist would be, but I wasn't anywhere near being right. Camden is definitely a little different, possibly autistic although that's never stated. The interaction between the agents shows a close relationship and understanding of each other's strengths.

All in all, this was a solid mystery filled with puzzle pieces and intrigue. If you like a detective novel where the killer is playing a game with the police, then this is for you!

Thank you to @Minotaur_Books and @NetGalley for a digital copy for review consideration. All opinions are honest and my own.

The oddball PAR team of the FBI is tasked to solve the case of a serial killer whose victims are all serial killers. PAR has a computer analyst, a weapons expert, a mathematician and is lead my a career agent - all who have pissed off internal FBI agents at some point in their career (which is how they ended up in PAR). This new serial killer is learning about the members of PAR and going after them as well to make sure he/she’s not caught.

This one totally gave me Department Q vibes (a Danish noir series about a ragtag department working in the basement solving cold cases) - I loved the non conformists working in PAR and am very excited that this seems to be the first in a series. I had both the audio and ebook of this, but got so caught up in how well the narration was for the audiobook that I barely read this one and simply listened. This was well written thriller and kept me engrossed the whole time as the team chased the killer. Head Cases came at the perfect time for me since the Department Q series just ended.

Thank you to Minotaur Books and NetGalley for the ARC to review

Wow what a book. I loved the diversity of the characters and the way the main character’s brain worked. It was truly an interesting read. This book was a genre that has been done lots before but I left this had such a fresh take on the profiler/FBI storyline. I can’t wait for book 2!

5 stars
Expected publication date - January 28, 2025

Thank you, NetGalley and St. Martin's Press, for this eARC for rewiew. All opinions are my own.

The PAR Unit of the FBI (Patterns and Recognition) investigates complex cases. The members of this unit are also complex individuals. The other units refer to them as "Head Cases" due to the kinds of cases they work on and the people who make up the unit. This case appears to be a serial killer whose victims are.....other serial killers. As they narrow the pool of suspects, they start to wonder if he could actually one of their own.

I loved this story, and I loved the characters. I hope to read more books in the future in this series and learn more about these characters. I will also definitely be reading the authors other work.

Thank you NetGalley and Macmillan Audio for sending this book for review consideration. All opinions are my own. When the FBI gets a case no one else can solve, they call in the Patterns and Recognition team. The PAR team has a variety of specialized skills, pulled together for their ability to see what other agents may miss. This is a group of misfits who have experienced failures on other team, which has put them in the crosshairs of FBI leadership. Their latest case has also put them in the crosshairs of a serial killer. Will they find the killer before leadership shuts them down? Acclaimed author John McMahon returns with Head Cases - the debut of the new PAR Unit series. Known for the PT Marsh detective series, McMahon latest work has already been optioned by HBO Max before it's even hit shelves! This is a book about leaning into strengths others may see as weaknesses, but also a realistic look at how loss impacts each of us differently. With mystery, drama, and relatable characters, this book will keep you engaged and entertained the entire way. I give Head Cases 5 out of 5 stars. I connected with the main character and got pulled into the storyline from page one. I enjoyed the mystery and will admit I didn't figure out who the criminal was until the author revealed in later in the book! The only holdback I had on giving this a perfect 5.0 rating was a few slight errors when referencing locations in Georgia. In one specific example, the author references a location of "south of Atlanta". Having lived south of Atlanta all of my life, that typically references locations that are still north of Macon - the location in the book was several hours further south nearly to the Florida border. If you love Karen Slaughter's Will Trent series, Marc Cameron's Arliss Cutter series, or the Jack Ryan books by Tom Clancy, you will love this book! It would also be a great choice for a mystery or crime book club - there is so much to unpack about the main character and the crimes. With gun violence, death, and serious injury, I would direct this to readers over 16.

I’m not one to grab all the procedurals out there, but I dabble when one throws a spark. ⚡️ I love a character who has learned to take a weakness and hone it into a formidable skill set.

Gardner Camden is a FBI agent and a member of PAR (Patterns and Recognition). They may be talented, but each member has been reprimanded for wrongdoing and is on the team as a punishment. Nevertheless, the team is clever and close knit. They have a reputation for solving the cases that leave other teams baffled.

They get called in when a serial killer is found murdered. The kicker is this particular killer was found dead in a fire years ago by Camden. Soon another serial killer is found dead. The team realizes this murderer knows more about the FBI than any civilian should.

How will the team protect each other and their families?

Who is the next target?

In less than twenty-four hours I was wondering how I could be finished with this. My brain never stopped turning over possible scenarios. The PAR team has flaws and strengths that fly off the page in brilliant form. There are no strapping hero stereotypes; these are underdogs that I wanted to root for and understand. I liked spending time with these well developed characters. I’ve been to many of the places and landmarks mentioned and the descriptions were top notch.

The way the plot unfolded was brilliant and it felt like the pacing was timed perfectly.

Well done!! 👏🏻 👏🏻👏🏻

All the stars!⭐️

Many thanks to NetGalley and St. Martin’s Press for providing an Advance Reading Copy for review. These are my unbiased opinions.

Not the story I expected. I thought this was about different FBI cases but was actually a fictional FBI story that was a special group of really smart but unusual agents hunting down a serial killer. Lots of facts and lots of action. It really sped up at the end, and I read the 2nd half in a few days. Great for anyone who likes procedural mysteries!

A group of socially awkward FBI agents are tasked with finding a serial killer who is killing serial killers. I loved the inner workings of the group, but found there were just too many characters to keep straight. Between the agents, victims and family members I didn’t know who I was reading about at times.

I did an immersive read, as I also got the arc audio of this book. Both were excellent. The narration was really intriguing and I loved being able to follow along with the book. I rated both versions a 5 stars.

FBI agent Gardner Camden is called into the case of a recently dead serial killer, that was declared dead years ago. The case takes off when more criminals begin to die in the same way they killed their victims. Camden calls in a special team of agents he knows can solve these murders, each agent specialized in different areas of crime.
This is a fast paced mystery that keeps you guessing until the end is near. I read this book in two sittings because it was such a page turner. It's a great read with plenty of suspense.