Head Cases by John McMahon is an intriguing mystery/thriller with some fun twists along the way making for an entertaining read.

The FBI’s Patterns and Recognition (PAR) team is comprised of five brilliant agents tasked with solving cold cases. Each with a specific skill set needed to solve the clues and close the case. Their latest case is far from cold and involves a vengeance seeking vigilante who thinks they are helping the FBI with their misdeeds. PAR sets out to show just how wrong the killer is and put an end to the case.

The characters could use a bit more development but were very likable and you will find yourself rooting for the team to bring down the “bad guy.” I would love to see this become a series so I can follow the PAR gang on their next case.

Many thanks to NetGalley and St. Martin’s Press for the advanced reader copy in exchange for my honest review.

Wow.
One of the best crime, murder mystery thrillers I have ever read! Serial killers, autopsies, hidden clues, gore, misdirection! This book has it all! Every time I went to put this book down I was met with cliffhangers, new information, jaw dropping moments that had me continuing to turn the page!
So much information: criminal, law geographical, biographical, botanical, mythological. And yet I was never lost or confused! Great writing and an even greater plot!
I absolutely will be buying the physical copy of this book to promote and share!

Thank you NetGallery and St. Martin's Press for the eARC for my honest review!

True crime fiction junkies, listen up! This is a MUST READ! The “Patterns and Recognition Unit,” led by Agent Gardner Camden, are a group of misfit FBI agents who are tasked with solving cold cases. Racing against the clock to track a serial killer, this thriller is nonstop action and totally bingeworthy. Clear an evening and dig in!

Thanks for the opportunity to read in advance. This one is going to be big!

“Head Cases” by John McMahon is about a search for a serial killer who is out to killing other serial killers in a grizzly fashion. DNA has shown that the killer who was presumed dead a long time ago, is alive and leaving a trail of riddles and clues. To find the killer a specialized agent from the FBI’s PAR (Patterns and Recognition) unit is tasked to solve the case. He is a unique person and has the ability to see strange patterns and numbers unlike anyone else. Along with other quirky agents on his team we follow them across country as the victims add up and they try to piece the many puzzling clues together.

The beginning of the book was interesting but the second half was a slow burn. I also had a hard time liking the characters so I never got fully invested in their success. I do think if you were a fan of the TV show Criminal Minds, this mystery/thriller will really appeal to you.

Thank you NetGalley and St. Martin’s Press for the ARC of this book in exchange for my honest review.

Wow! I didn’t know what to expect with this book, and I was blown away. I truly enjoyed this, and it needs to be a book series (or TV series!!) ASAP. I love the characters and their quirks. The pacing was perfect - it kept me intrigued to continue reading and I didn’t think there was unnecessary “fluff”. I will be recommending this to others!

Head Cases opens with a series of grisly murders that appear to be an act of vigilantism. Someone is killing murderers in ways that appear connected to their crimes. Enter PAR, a team of puzzle solvers and brilliant outcasts tied together not only by their intellect, but by their blemished careers. Central to the cast is Gardner Camden—Gardy—in a new leadership role.

Gardy is as brilliant as he is awkward; a good father and connected to his mother who suffers from dementia. He quickly begins to piece together clues with the help of his team, kicking off a race to identify and locate the killer who might be one of their own.

An overall well written novel, Head Cases hooked me with its intelligence but lost me in its deep procedural delivery. I don’t read strict procedurals so perhaps this is one of those “it’s me, not you” things, but I needed a subplot that wasn’t Gardy-centric. I didn’t identify with him nor did I come to like him despite his love for his mother and daughter, which were his most redeeming qualities for me. Procedurals can become dry without something else going on. Once the victims were identified, the pacing failed to hold my attention. The mystery became muddied by the bureaucracy of PAR. Gardner never emerged as someone I wanted to root for. That doesn’t mean this isn’t a good novel. It just wasn’t great for me. I would recommended it for fans of awkward main characters and police procedurals.

Head Cases was an enjoyable read that I think will resonate with any fans of Criminal Minds. I enjoyed as the team put the clue together to track down a serial killer or serial killers. Overall, I give this book 3 stars. The premise was interesting but the ending fell flat. I also had difficulty keeping up with how many characters there were.

Thank you St. Martin's Press, John McMahon, and Netgalley for allowing me to read this ARC.

"Head Cases" by John McMahon is a thriller mystery novel, featuring a team of FBI agents who are very talented, but screwed up big in some way or another, so they have been relegated to the PAR (Patterns and Recognition Unit). When a former serial killer is found dead (and was already declared dead in a fire years ago), the PAR team is enlisted. Agent Gardner is put in charge of this case and is coded as neurodivergent, Sherlock Holmesian in his deductions. This novel is like reading a "Criminal Minds" episode, only better. Lots of twists and the action moves quickly. A recommended purchase for all fiction collections.

Whiplash! This books has some many different story lines-it was so hard to keep track of where you were in this book. I really had to pay attention to follow along. Overall it was ok.

Thank you to the publisher for making this available to read through NetGalley for its influencer program.

Head Cases centers around FBI Agent Gardner Camden and the Patterns and Recognition (PAR) unit, a quirky group of misfits tracking down a killer out for his own brand of justice. I found it well paced and smoothly written--I had a hard time putting this down once I started. But at the same time, there were a couple things I'm not entirely sure of.

First, and I realize this might be entirely subjective for me, but for crime fiction to really work, you have to have sympathetic victims to create immediacy in the plot. You rally around law enforcement if the killer is going after innocent children and damsels in distress, if you will, and there's an element of suspense not knowing who the next victim will be and if they'll be saved in time. The choice in Head Cases to make the victims serial killers, while interesting and different, takes away that suspense. Quite frankly, take your time, FBI.

Secondly, and also subjective--the characters themselves. I liked them all well enough; the PAR team is a likable crew. But there's something a little cliché about Camden and Shooter in particular--one a socially inept genius who'll be able to pull facts no matter the subject, and the other an Olympian, literally a "shooter," that again took away some of the suspense for me. That they'll be successful never seemed to be in question.

That being said, if this will be developed into a series, I would definitely check out book 2, hoping that the elements I was missing are there. But not knowing anything about a second installment, I'm not entirely sure if I would recommend this. A solid read nonetheless, 3.5 stars that I would round to 4 because I liked it in spite of the problems I had.

Head Cases is a fun book to read if you’re a fan of Criminal Minds. A team of FBI agents attempt to track down a serial killer of serial killers. I really liked the concept of this “rag tag team” of agents with very specialized talents being a specific group that solves cold cases. The overall plot is good, although a little too procedural at times. The writing is strong, but the written dialogue for Cassie’s character was cringey a majority of the time (the gen z language felt so forced). The end definitely felt like there was a door left open for a potential series. I think with a little more character development, this would turn into a strong series. (4.25/5)

**This ARC was provided by the publisher via Netgalley in exchange for an honest review.**

Thank you to NetGalley, author John McMahon and St. Martin’s publishing group for the ARC and opportunity to review this book.

3.5 stars rounded up. This was my first by this author and I quite enjoyed it. I loved the characters and would hope to see this ‘crew’ become a series if they aren’t already.

The storyline was good, it kept my attention but I feel it was missing something to make it a little more gripping and suspenseful. I felt it jumped a bit too much and had to re-read a few parts to make sure I was understanding which character, which crime scene etc but the author tied it up nicely in the end.

I would recommend if you are looking for a slower paced brain teaser type of book. I felt it would make a great episode of criminal minds!

3.5 ⭐️⭐️⭐️

It took me a while to warm up to Gardner and his Head Cases in the FBI PAR special unit. Their idiosyncrasies come together to solve a crime of serial killer killing serial killers. Office politics play a large part as the navigates their rumored demise. its intensity reminds of Criminal Minds. I love the relationships Gardner has with his mother and daughter. I will definitely read what comes next.

Copy provided by the publisher and Netgalley

Thank you to NetGalley and St. Martin’s Press for this ARC!!!


I would change absolutely NOTHING about this novel. It literally felt like reading from Spencer Reid’s mind from Criminal Minds. I finished this book in less than 24 hours because I could not stop. Definitely hope this turns into a series.

I flew through this book! I really enjoyed the story line and the true crime/FBI/criminal minds feeling. I also loved the plot twists and the constant chase through the entire book. I appreciated how focused to the hunting criminals plot this book was, without many side plots that distracted from it. I’m taking a star off because I felt like I was able to predict a few of the bigger plot twists and didn’t love the way this ended. I did appreciate that this was a stand-alone and thought it was overall well done!

If you're craving a page-turner that will give you the perfect escape during nap time or after the kids are in bed, you have to check out Head Cases! This book is packed with suspense and drama that will keep you hooked from start to finish. IT’s the perfect "me time" book!

Head Cases by John McMahon is a fast paced police/FBI procedural crime novel. Gardner Camden is part of the PAR unit of the FBI, which is a Patterns and Recognition group of four agents. These agents are used when others in law enforcement haven’t been able to make headway in a case, PAR being a fresh set of eyes for such a case. Agent Camden is a unique individual, probably considered neurodivergent, and sees numbers and patterns unlike anyone else. He is also an extremely likable character who readers can instantly connect to and root for. The rest of the crew have their quirks and individuality as well, and it is obvious they are more family than just coworkers.
The case PAR is brought into on page one is the murder of a serial killer thought to have died seven years prior. The killer left clues seemingly for Camden himself. And before you know it, he kills again. A serial killer killing serial killers!
Off we go on a nonstop journey from Florida to Texas to California and back again, piecing clues to the puzzle together to solve the crime. Camden’s personal life gets involved as well, which just adds to his humanness as a character.
I was impressed by how realistic the conversations were and honestly at times felt like I was part of the unit trying to solve this crime. It definitely gives you an image of intense excitement being an FBI agent, which was a childhood dream of mine, so a fun reading experience. I would liken this to Sherlock Holmes with his quirky and clever mind or genius Spencer Reid from the show Criminal Minds. If you are a fan of this genre, I think you will really enjoy this read. And P.S. there are plans for a sequel which I will definitely pick up. Thanks to NetGalley and St. Martens Press for my ARC.

A scooby-doo rag tag gang of the FBI who have been shunned make up the PAR, Patterns and Recognition Unit. FBI agent Gardner Camden is lead of this group, and with his brilliant mind but awkward social skills, make up this stunning thriller and police procedural novel.
An absolute binge worthy read and great for everyone, even those who don't fancy themselves as crime junkies!

I loved this one it kept me guessing the whole way through! This is a perfect Fall thriller I highly recommend!

Head Cases follows Agent Gardner and the PAR (Patterns and Recognition) group that handles cold cases. When they get a call for a murder victim whose DNA links to a man that Agent Gardner believed to be dead, it sets the PAR group on a hunt for a killer who is targeting other serial killers. Can the PAR group who is used to working in the background, handle working on a current case in the public eye?

This book took me by complete surprise. I loved how different this book was from the mystery/thrillers I have read recently. Agent Gardner is the perfect main character for this book. It was nice to see a character that was neurodivergent, and I enjoyed reading his thoughts as he navigates through the case and how he interacted in social situations while leading the PAR team. This book had me completely engaged from beginning to end and the conclusion took me by surprise. The ending did open up the possibility of another book and I would read that in a heartbeat.

If you enjoy police procedurals and/or mystery thrillers, put this on your TBR for 2025.

Head Cases comes out January 28th, 2025.

Thank you to NetGalley and St. Martin's Press for the opportunity to review Head Cases. All thoughts and opinions are my own.