“The expression serial killer is just a convention of man…at the end of the day, every killer is just a human, searching for something.”

Police procedurals are pervasive in the current entertainment sphere. Ones with complex and compelling plots narrow the field. But the ones with incredibly well drawn characters who show us all the in-betweens are rare. It’s no surprise that the film/tv rights have already been sold for this novel and I’m already looking forward to the next in the series!

I’m reluctant to compare Head Cases to the brilliant Slough House book series by Mick Herron, but in this case the correlation is deserved. Just as the MI5 has a niche group of misfits, McMahon has created a similar group within the FBI. The PAR (Patterns And Recognition) unit is comprised of agents, demographically different, who share a lack of adherence to the norms. They are all incredibly talented in ultra specific ways but have run into political roadblocks along their career paths. The group itself (nicknamed The Head Cases) is in danger of being dismantled and the players operating within are in danger…period. As they hunt down a serial killer who is killing infamous serial killers, their skill sets and their vulnerabilities come into focus. Law enforcement and politics combine like oil and water and in this case, create an incendiary device exploding with collateral damage.

Smart themes, snappy dialogue and fresh perspective made this a fabulous one sitting read for me. Bravo Will Damron for bringing these quirky and diverse characters to life!

Thanks to Net Galley, Minotaur Books and Macmillan Audio for the early copy in exchange for my honest review, which will be promoted on my Instagram page @bookshelfbybeckwith, Goodreads, Amazon and Barnes & Noble closer to publication day.

Head Cases is a puzzle you are trying to solve as you read. How can a serial killer who is dead leave his DNA on a murder victim? The PAR (Patterns and Recognition) unit of the FBI is on this case and has an expert in every field that they need to crack the case. Agent Gardner Camden is great at puzzles and putting the pieces all together. They figure out when the murders continue that a serial killer is killing serial killers. Great read for anyone who likes reading about crime and serial killers!

Thank you to NetGalley and Macmillan Audio for the advanced copy of this book.
I loved this book. John McMahon is a new to me author and I am so excited to see this was book #1! The premise of this book was an FBI special unit that was tasked to hunt a serial killer that is killing serial killers. It had everything a thriller/psych thriller/mystery should have. I loved Gardner Camden, the main character and his team, the way that they look and process the clues they come across.. Listening to the audio, the writing was so descriptive it was almost like I was with the team seeing it with my own eyes.
This book is full of unexpected twists and turns that will keep you guessing at every turn. If you're like me and you love a good thriller/psychological thriller, this read will grip your attention and keep you captivated until the very last page!

I really enjoyed listening to this audio! I was a little confused by the plot, there were a lot of characters and things to keep up with. Maybe I will have to do a reread at some point, but I enjoyed the time I spent listening all the same!! Definitely twisty, turny, and thrilling!

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 author crafts scenes with detail and authenticity that bring them to life off the page – I can understand why this was picked up for the screen! 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 have recently been watching the Netflix “Mindhunter” about the early days of serial killer profiling in the FBI, so I was immediately drawn to this novel when read the description on NetGalley. I love police and military thrillers and this was right up my alley. Head Cases will release on January 28th – you can preorder you copy in our Bookshop.org store today!

I am excited to share I recently discovered a new, exciting author and thriller by John McMahon that will keep readers on the edge of their seats.

A gripping new thriller by John McMahon that promises to keep readers on the edge of their seats! This intense narrative delves into the chilling world of serial killers through the lens of a uniquely formidable group within the FBI. When a wave of serial killers turns up dead, the elite Patterns and Recognition (PAR) Team springs into action. Led by the brilliant Gardner Camden, they race against time to track down a new killer while being taunted by a mysterious vigilante.

Determined to halt the escalating violence and bring their prime suspect to justice, Camden and his team must stay one step ahead in a complex game of cat and mouse.

McMahon crafts an action-packed tale that grabs your attention from the first page. Those acquainted with Gardner Camden's thinking know he's a master at piecing together puzzles, often spotting details that elude everyone else. Some might see his talent as a hint of autism or savant-like abilities, but his unique perspective is invaluable in the high-stakes world of the FBI.

Typically called in when other teams falter, the PAR Team excels at solving cold cases. But this time, they're thrust into a fiery scenario where discretion is paramount. Camden— is faced with the challenges of untangling a web of deception while confronting the shocking resurgence of a supposedly dead serial killer. The dynamics of Camden's personal life add another layer of complexity to the narrative. His struggles to maintain a relationship with his estranged wife and daughter, who struggle to understand his quirks, and the dedication he places on his job further humanize him while serving to illustrate the psychological toll of his profession and the societal disconnect he faces due to his analytical disposition.

As bodies of serial killers pile up, the team grows increasingly uneasy about the possibility of a vigilante on the loose—someone bent on cleaning up the remnants of the FBI's past failures. The stakes couldn't be higher, with rumours swirling about the PAR Team's imminent disbandment. When the elusive killer begins to toy with Camden, leaving behind cryptic clues, the countdown begins to unveil a foe determined to make their mark and ensure these brutal killings don’t go ignored. Gardner Camden may finally have met his match unless he can uncover the missing link.

John McMahon delivers an electrifying thriller that keeps you guessing at every turn. The narrative unfolds rapidly, weaving together a complex tapestry of clues that propel the story forward with relentless momentum. As the tension builds, readers find themselves piecing together the mysteries, only to be met with unexpected twists that heighten the intrigue. Key characters are richly developed throughout, each offering tantalizing glimpses into their pasts, leaving ample room for future exploration.

With constant revelations and surprises, the plot maintains a sense of ongoing mystery that gradually unravels hidden truths. I eagerly await John McMahon’s next installment featuring Gardner Camden, whose enigmatic character has much more to reveal.

This book is a must-read if you love well-paced, non-stop action, solving puzzles, and unravelling mysteries with compelling, realistic, richly developed characters, and you enjoy crime procedurals— prepare yourself for a rollercoaster ride of unexpected twists and turns that will keep you guessing at every turn. For those with a flair for tracking serial killers, this exhilarating read will surely grip your attention and keep you captivated until the very last page!


I had a wonderfully immersive reading experience as I alternated between the audiobook and my Kindle. Will Damron's narration truly stood out; it was fantastic. He brought the character of Camden to life in a way that felt incredibly authentic and relatable. It was as if he had stepped right into Camden's shoes, allowing every moment of the story to resonate deeply with me.<br/><br /><b>I would also like to express my gratitude to St. Martin's Press/Minotaur Books and Macmillan Audio for providing a copy of the e-arc and a copy of the ALC through NetGalley in exchange for honest feedback. All opinions expressed are my own.
The expected release date is January 28, 2025

“Head Cases” by John McMahon is about a unit within the FBI called PAR (pattern and recognition). On this case, they are searching for a serial killer who is out to killing other serial killers in a gruesome manner. DNA has shown that the killer who was presumed dead a long time ago, is alive and leaving a trail of riddles and signs that will lead the PAR Unit to him.

Liking the characters was so easy for me and I was fully invested in their success and downfalls. This is a police procedural, special unit story and a thriller/mystery all rolled into one. It is fascinating in its construction, the weaving of the characters, the perfect red herrings to the end and entertaining the whole time. I definitely recommend Head Case. I can’t wait to read the second book in the series in early 2026.

Thank you to NetGalley, the author, John Mc Mahon, and the publisher St. Martin’s Press/ Minotaur Books for the opportunity to read and review an advanced reader's copy of Head Case.

I was sold with Head Cases as soon as I saw people saying it's a good read for fans of Criminal Minds. I'm glad I listened because this was SO good! Serial k*ller / FBI cat and mouse stories are one of my absolute favorite types of crime fiction reads.

Great story. Great characters. Great narration. 4 stars!

5/5 stars

Thank you Macmillan Audio for the advanced listening copy!

I loved this book from the start! Total true crime vibes, and it almost read like a documentary. Listening to this on audio only enhanced that; Will Damron did a great job encapsulating our MC, quirky, lovable and brilliant Gardner Camden. I loved Gardner's character and following his thought process was extremely fascinating. This book kind of reminded me of UNMASKED by Paul Holes or BRIGHT YOUNG WOMEN by Jessica Knoll -- so if you liked either of these, you'll love this one. I found HEAD CASES to be even more interesting than either of those others -- both of which I loved -- and thought it wrapped up really nicely. Any serial killer story is going to be naturally interesting, but this one took a number of unique twists and turns that kept me so hooked from the beginning. Great way to end 2024's reading list!

Gardner Camden leads the Patterns and Recognition (PAR) Unit of the FBI, a cast of quirky characters with unique skills to solve crimes. The team has been called in to investigate the death of a serial killer they thought dead many years ago. Through the investigation we learn about the history of the team and their backgrounds. It was an interesting mystery with good pacing and enjoyable characters.

I enjoyed this first in a new series and look forward to future installments. The narration was good as well

Thank you to #NetGalley and #MacmillanAudio for a free copy of #HeadCases by John McMahon. All opinions are my own.

Gardner Camden and his team make up the Patterns and Recognition (PAR) unit of the FBI. This 5-member team consists of agents who are considered "misfits" - in one way or another they've messed up in the past and have been shuffled off to anonymity. They're a quirky bunch but brilliant in one way or another. A serial killer from one of Gardner’s solved cases, presumed to be dead for over a decade, is found murdered and another body with a similar story soon after. The murderer has left clues and riddles for Gardner and his team as they track him across the country. With the threat of PAR being disbanded, Gardner must work to solve the riddles before it’s too late.

I really enjoyed this story and these characters and will continue to follow the series when other books are available. I was exhausted following Camden back and forth between Texas and Florida and points between. He seemed to be constantly on a jet going somewhere. He is really "special" as his mother will tell you. This is the second book recently where prime numbers played a big role in a character's thought processes. I enjoyed the flashes of humour from some of the characters, even Gardner although he had to explain it was a joke. There was plenty of tension and "oh no" moments to keep the suspense ratcheted up and I was happy with the ending.

This is my first experience of an audiobook narrated by Will Damron (I wonder how often he gets called Damon?!) and he did an outstanding job voicing the different characters. I kind of wished there had been a female narrator as well since there were quite a few female characters including a young girl but Mr. Damron did a fine job with their voices.

My thanks to Macmillan Audio via Netgalley for granting my request to listen to this audiobook. All opinions expressed are my own.
Publication Date: January 28, 2025

This cat and mouse game between a serial killer and a group of FBI misfits was such an enjoyable read! Each of the FBI agents have their own special gifts to provide to the case which makes the chase all the more fun to watch play out. Will Damron does a wonderful job narrating, boosting the quirky personalities of each character with his voices and overall charm.

This is another book I had the pleasure of reading with my booksta besties and we all enjoyed it so much! Again, we spaced it out over five days but this one is entirely bingeable and you’re not going to want to put it down!

I loved Head Cases! The story is gripping, emotional, and thought-provoking. The writing pulled me in, and I couldn’t put it down. I highly recommend this book to anyone looking for a powerful and engaging read.

Thank you to NetGalley and MacMillan Publishers for the ARC in exchange for a review.

This book was absolutely fantastic. Anything that comps Criminal Minds is a winner in my book. The story was really interesting, but what made it for me was the main character, Agent Camden. He was similar to Dr. Spencer Reid (from Criminal Minds, of course) but more awkward. I genuinely enjoyed the perspective of an ND character that was realistic and easy to get attached to. The way his mind worked was so intriguing. And I’ve always been interested in the phenomenon of an eidetic memory. The way the author incorporated Agent Camden’s traits worked so seamlessly, but also the way the other characters interacted with him and reacted to him. It was very realistic from an ND point of view. I genuinely enjoyed the case itself and am looking forward to more from this series!

Huge thanks to Macmillan Audio and NetGalley for sending me this ARC for review! All of my reviews are given honestly!

I am a huge fan of McMahon's first series about P.T. Marsh and so approached this new series with a bit of trepidation. I needn't have worried. While quite different, this is the start of another great series. The "Head Cases" refers to the members of the FBI team, each eccentric in their own way, while being quite brilliant at their specialty. The main protagonist is Gardner Camden, firmly on the spectrum, who ha a talent for patterns and puzzles. PAR's target is a serial killer who is klling....serial killers. While the book does occasionally skate close to the line of going OTT, it is thoroughly enjoyable and highly recommended.

I want more!

I loved Gardner Camden, our main character. He’s smart, quirky, and stands out as unique in this oversaturated thriller genre.

The murder mystery is complex and keeps a steady pace throughout. The story is well plotted and easy to follow, but there are lots of pieces and you need to pay attention in order to put together the clues.

I alternated between listening to the audiobook and reading my Kindle copy. Will Damron does a fantastic job with the narration. He fully inhabited Camden’s character in a way that felt honest and real.

I’m so excited that HEAD CASES is the first in a series!

*Thanks to Macmillan Audio for the free audiobook download, and to Minotaur books for the free eARC, provided via NetGalley!*

Gardner Camden, a genius with an eidetic memory, is pulled back into a case he thought was closed 7 years ago. Now part of the quirky and often ridiculed PARS team, Gardner brings his sharp mind to a high-stakes, fast-paced investigation.

I love a quirky genius, so I jumped at the chance to listen to this audiobook. The narrator absolutely nailed Gardner’s personality and accents, which added so much to the experience.

I’m not usually into procedurals, but this one struck a great balance between the case and the team dynamics. Gardner’s mom was my favorite character—her introduction was just perfect.

The case itself was intense and addictive, constantly throwing twists at me. Sure, the outcome and setup for the next book were a little predictable, but honestly, I didn’t mind. I’m thrilled this is a series and can’t wait to see more from the PARS team.

Thanks to Netgalley and Macmillan Audio for access to this audiobook ARC in exchange for my honest review

A book about serial killers with a main character who has difficulty with social situations and an eidetic memory? Sign me up! I started out listening to this book but then wanted to finish it sooner so got out my kindle and finished it up in a couple hours.
This book follows the PAR team at the FBI. A rag tag group of misfits as they race to solve a case that they can’t get ahead on.
I honestly loved every minute of it! Can’t wait to read the next one.
I received an ARC of this title, all opinions are my own.

The head cases are a group of FBI agents that specialize in Patterns and Recognition (PAR)
When Gardner Camden, one of the PAR unit, is called to a crime scene, he finds out that the deceased man is a serial killer that he found at a crime scene seven years ago. Now he’s on the hunt for the serial killer that kills serial killers.

This book was narrated by Will Damron who did so well 👏🏻 the story immediately sucked me in, and I had a great time listening / picking up my e-arc at times I couldn’t listen.

This one is for fans of David Ellis and James Patterson! I love a good police procedural with quirky characters and this one delivered.

Thanks so much to NetGalley, St Martin’s Press for my ARC and Macmillan Audio for my ALC.

Pub date 01.28.25

Head Cases, written by John McMahon and narrated by Will Damon is a fictional book written about PAR, the Patters and Recognition Unit of the FBI. Gardner Camden is our main character, and a member of the unit. He has a great mind for puzzles, riddles, and codes, but still struggles with some of his social skills. He is part of a great team, where they can work together and help each other, which he comes to really appreciate and count on in this book! This is especially important when a serial killer from one of Gardner’s solved cases, who has been thought to be deceased, is found murdered . And when Gardener starts getting messages from the unknown killer, he knows he needs to find some patterns before it is too late!
I did not know much about this book going into it, but I really enjoyed it! The main character reminded me a lot of Will Trent, a special agent from another book/television series that I like. I appreciated that the team members were able to work together and recognize the strengths that the different individuals had, and I also enjoyed the presence of Gardeners daughter and mother in the story. I definitely recommend this book to crime and mystery readers, and I look forward to reading more books by this author in the future!
Thank you to NetGalley and to the author, publisher, and narrator of this book for an ALC in exchange for an honest review.