Head Cases is a serial killer super-thriller following FBI agents of a PAR unit (Patterns and Recognition) gathered to solve two gruesome murders. Agent Gardner Camden, a genius with an eidetic memory, heads up the team which includes the usual team leader in the group, but Gardner is unaware of why he has been put in charge, and senses there is more to it than meets the eye, in relation to the continuation of PAR within the Agency. The first body is discovered to be a serial killer who died seven years earlier in a house fire, and when PAR links the second killing, the team has to follow puzzles and clues deliberately left by the killer.
Contemporary thrillers are not my usual genre of choice, but this one gets high marks from me for ingenuity. A complex murder spree becomes even more puzzling as the reader is taken inside the FBI’s top echelons, with a small group of talented dedicated agents whose unconventional characteristics are a big part of the addictiveness of this story. Recommended to readers of quirky thrillers.

I ate this one up! I love a good police / serial killer mystery and this one delivered. I loved Gardner and his quirks and getting to go along with him as he tried to solve the murders. Cassie is a fun side character as well! I'm excited there is going to be another in the series!

Reading this book felt like I was immersed in a Police Procedural Crime Drama. I binged this book this book in an evening and then went searching to see if this was going to be a future series because I think it definitely should be.

I really enjoyed the author's writing style and found the storyline to be really intriguing. It's fast-paced and there is enough twists to keep you on the edge of your seat turning pages.

This is a new to me author and I am looking forward to reading more from him in the future.

Thank you John McMahon, Net Galley and St. Martin's Press - Minotaur Books for providing me with an ARC of this book!

Gardner Camden is a socially-awkward genius with a knack for solving puzzles. He is the book version of Spencer Reid and I love it. He works for the FBI in their special patterns and recognition unit (PAR)...again, Spencer Reid.

When a body shows up of a killer that was presumed dead, PAR jumps into action. The killer leaves them clues and puzzles for PAR to solve to try and catch him, but will they catch him in time? The unit races against the clock to track down this vigilante before they get shutdown for good.

Head Cases was a fast-paced thriller full of twists and turns that keeps your mind spinning. I finished this book in a matter of DAYS because I needed to know what happened. 10/10 love this author!

Thank you to the author and St. Martin's Press for an ARC. This is my honest and voluntary review.

Thank you to NetGalley and Minotaur Books for an e-ARC, available everywhere early next year.

When it comes to prominent departments in the FBI, working in the Patterns and Recognition (PAR) unit is hardly on anyone's wish list. For Agent Camden and his team, it's difficult to picture them anywhere else, even if they are typically found behind a desk. Often brought in on cases that no one else can solve, they are surprised when their newest case leads them into familiar territory: a murder victim is allegedly a serial killer long thought to be dead. As Camden grapples with this blast from his past, a similar victim turns up. Pulled into a tense game of cat and mouse, the unit heads on the road, hoping to solve the riddle before it's too late.

I liked it a lot, appreciating the dialogue and the writing, though I didn't think Camden was as odd as he was portrayed to be. I was also on edge for most of the novel, becoming more nervous as it went on. There were definitely a few surprises, and the question of the killer's motive was a good way to keep people guessing. I want to go back and re-read a few chapters because even now I'm still questioning the chain of events. At one point, it looked like the author was trying to shoehorn in a romance (or at least a flirtation) between two of the characters, and I'm really glad that didn't happen. I'm not sure if this is the first in a series but if there was a sequel, I'd be interested to see where it goes and how the author can top this one.

4.5 Stars
Heads cases follow a group of brilliant yet quirky FBI agents. Agent Gardner Camden is a genius who has an affinity for puzzles, but he isn't so great with people. When DNA links a presumed dead serial killer, PAR (Patterns and Recognition) Unit springs into action. While they usually solve cold cases from the office, this case forces them into the public eye. Will they be able to keep their family safe and identify this killer before it's too late? Find out January 28, 2025!
If you loved the YA series, The Naturals by Jennifer Lynn Barns, you would absolutely love the adult version of it! This is my first John McMahon book, and I can confidently say it won't be my last. This was a fast-paced thriller that kept me on the edge of my seat. I was hooked from the very beginning! I grew up watching criminal minds and the main character reminded me of a more direct Spencer Reid.
The plot was well thought out and am I sensing a tiny romance subplot…? I loved Cassie as our main characters partner. She is able to communicate and understand Gardner without having to push him into confiding in her. I was completely immersed in this book and that had a lot to do with the writing style of the book.
It looks like there may be another book to continue this series and I cannot wait!!!
Thank you to Minotaur and John McMahon for the early copy!

An extremely readable, forensically detailed investigation of a serial killer with more zigs and zags than a whole chain of Texas thunderstorms.

The protagonist is a socially awkward, neurodivergent-coded (Bones, Monk) lead detective from a fictional FBI squad that mostly sits in rooms reevaluating evidence that other agencies have gotten lost on or cocked up somehow. Now, with murdered serial killers piling up round the American south, the pressure is on to figure out who knew where these guys were, what they’d gotten away with, and then managed to get them alone and vulnerable enough to do to them what they’d done to others.

Lead investigator, Special Agent Gardner Camden, is at once traumatized, chillingly meticulous, and deeply ethical. Kind of like Dexter, without the personal body count. Unlike Dexter, he doesn't have to fake loving his daughter or his mother, caring about his ex-wife and even her mother.

There’s a bit of graphic blood spatter and some gross references to organs but those aren’t the main focus. Just clinical, logical descriptions of crime scenes and careful deductive reasoning.. The evidence chases around the country, the suspects shift as one after another gets spotlighted.
The pace and tension rise with the stakes. It’s all very convincing and well plotted. There's a nice balance of teamwork and lone-wolf heroics, and lots of forest and swamp to balance the cool restraint of all those offices and airplane rides.

Well worth a weekend for fans of forensic thrillers.

Just the kind of "truly" true crime book I needed. Thank you to NetGalley and the publisher for the advance copy.

Do you like scintillating series debuts? If so, Head Cases by John McMahon is the book for you. This really is a terrific thriller. McMahon introduces us to the Patterns and Recognition (PAR) unit of the FBI and you'll quickly be enthralled by this group. In some ways it is like The X Files. In other ways it is like Department Q. And in still other ways they are like the Fabulous Five of Doc Savage fame. It's a riveting read with a strong case that is brought to a satisfying conclusion. I promise you'll be happy to know there will be a sequel. I was. Thank you to St. Martin's Press, Minotaur Books, and NetGalley for the advance reading copy in exchange for my honest opinion.

Head Cases, a nickname for a team of FBI agents known as PAR, have been called in to investigate the murder
of a serial killer who is belived to have died in a fire seven years ago. As the murder is being investigated, another
serial killer just released from prison has been murdered. How were the men tracked down and are the murders
connected in some way? When lead agent Gardner Camden is contacted by the killer, it becomes a race
against time to capture the murderer as he escalates. What will the past of the victims reveal and how does
Camden's role in the earlier investigations factor in? Intriguing mystery with twists and teams members who
each have a specific skill set.
#HeadCases #StMartinsPress #JohnMcMahon #NetGalley

Head Cases by John McMahon is an engaging read from start to finish with a well developed plot and characters. A recommended read!

Wow, I was captured right away and had a hard time putting it down! I enjoyed the point of view of someone who thinks differently and how they feel interacting with others. This book is well written, fast paced, and overall a great read. I will be looking into John McMahon's other books because this book was great!

Gardner Camden is the FBI agent you want if you have a murder case that looks unsolvable. "Head Cases" opens when Gardner and his fellow agent, Cassie, are called to a case in Texas.

The local law enforcement knew they were out of their league when they discovered that the victim had already been declared dead seven years ago. Gardner had been on the scene when murderer Ross Tignon's body was recovered following a fire in his home.

No sooner had Gardner and Cassie started on the Tignon case when called to another murder--of another murderer-- in another state. One by one, someone is eliminating murderers. No, it's not a coincidence. If you enjoy mysteries that take you hither and yon and back again, you will like "Head Cases" by John McMahon.

My favorite part of the book is Gardner. His mother told him that his mind just worked a little differently. He's not real strong with social skills, but Cassie gives him a good prompt now and then. Gardner's learning, thanks to a genuinely kind partner.

Maybe you'll figure out who the villain is before the end. I'd be surprised, but maybe you're another Gardner!

I recommend "Head Cases." The characters, the plot, the diversions-- all written so well it leaves you wanting the sequel right away.

Thank you to NetGalley for letting me read the advance copy. This is my honest review.

Thank you NetGalley for letting me read and review this ARC.

FBI agent Gardner Camden has been put on FBI´s PAR unit (Patterns and Recognition), who are brought in for cases no one else can solve. DNA shows up that links a murder victim to a serial killer who died years ago. The team starts working the case and a second victim shows up and establishes a pattern.

I am a HUGE fan of the TV-show Criminal Minds, which is probably what made my eyes catch onto this book. FBI agents and murder mysteries, I can´t really ask for anything else. In this book you get to follow agent Camden as his team tries to solve the murders, while also being threatened by the killer himself.

This was a twisty book and you have many suspects while reading it. I rated the book 3 stars.

Thank you to NetGalley & St. Martin's Press | Minotaur Books for this ARC! *Head Cases* by John McMahon is a fast-paced thriller that delves into the dark side of memory and trauma. The story follows a detective named P.T. Marsh, whose investigation into a brutal murder leads him into a web of corruption, deceit, and deeply buried secrets. McMahon masterfully balances psychological depth with gripping suspense, creating a complex protagonist who struggles with personal demons while trying to solve the case. The novel’s twists and layered plot keep readers engaged, with a well-crafted mystery that steadily builds tension. Fans of gritty crime fiction will appreciate McMahon's sharp storytelling and emotionally charged narrative.

The Pattern and Recognition (PAR) group of the FBI is made up of a group of brilliant misfits, all of whom have done something to anger the higher ups. Perhaps the most brilliant of them and also the most socially awkward is Gardner Camden. But he is also the most honest and the most dedicated to the FBI. When a serial killer starts killing serial killers- one of whom Camden thought had died 8 years earlier - the PAR unit is given the case and the typical bureaucracy that exists in organizations such as the FBI plays an important role in the story and Camden is put to the test. Hopefully, this is the start of a new series with Gardner Camden and his cohorts.

Summary
The FBI formed a task force with agents who are gifted with patterns and recognition. This group is referred to as PAR, at least to their faces, but behind their backs, they’re called the “head cases”. Each agent in this unit has a questionable background with bureau politics and has essentially been deemed unfit to be in the public eye. However, their knack for analysis and pattern recognition makes them a perfect fit to investigate cold cases.

But, when a suspected serial killer turns up dead, PAR is thrust into an active investigation. The deceased man was previously tracked down by PAR’s Agent Gardner Camden, but when they attempted to make the arrest, the suspect’s home was ablaze, and his body was identified with dental records. So, how is it now, that more than a decade later, the man has turned up murdered?

And when the body of another serial killer drops in short succession, it becomes evident to the team that they have a serial killer than is picking off other serial killers. PAR must race to solve the clues left behind, or risk being too late.

Review
This book gave me call backs to some of my favorite things. A little bit of Criminal Minds (Agent Gardner Camden reminds me of Agent Reid), and a dash of Dexter (serial killer vigilante justice).

Agent Camden was the perfect narrator for the story, he was likable and quirky with her neurodivergent nature. I loved the explanation as his mind teased out the solutions to various clues / riddles, but also understanding the inner dialogue of his perception of social situations.

Only thing I wished had been better was the development of the remainder of the PAR team. I felt like Agent Camden’s character was so well done, but then the other characters fell flat to a point where I wasn’t sure I really remembered any of them.

Great read though! I would definitely read more books in this series!

Head Cases
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If you’re a fan of Criminal Minds or similar FBI shows, you’ll be a fan of this one, it reads just like an episode! This is a cat and mouse type thriller, with quick chapters it’s a fast paced book you’ll probably want to binge. There were a lot of elements to keep track of, we’re solving right along side Gardner and his team so there are definitely a lot of information…names, dates, locations, etc, but I think the author did a good job of going over the information throughout the book, but not in an annoying repetitive way. It could be a little graphic at times, but nothing crazy (at least not for me lol). I will say that the ending, once we found out the reason behind everything, felt a little underwhelming, but overall I thought it was a good read! And I like the cover! If you love Spencer Reid from Criminal Minds or Brennan from Bones you’ll like our main character! I’m interested to see if this turns into a series? ⭐️⭐️⭐️⭐️
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Thank you NetGalley, John McMahon, and Minotaur Books for this e-ARC. Head Cases comes out January 28th!

When I first starting reading, I wasn't too sure I was going to finish it. I had a hard time connecting to the characters. I continued on and I am glad I did. I actually found myself hoping this was going to be a series and not a stand-alone. Spoiler alert - there is going to be another book!

Fast paced. Totally unexpected. Not having read this author before I didn’t know what to expect. I was surprised and excited by the writing and totally pulled into the plot of the story. My favorite show is Criminal Minds and so this was totally up my alley.