This was a 4 star book in my opinion. I am not overly familiar with this author but I will be looking for more books from him in the future!

This felt very much like an episode of Criminal Minds. Gardner Camden is on the hunt to find a serial killer who is killing other serial killers. I really enjoyed seeing the full story unfold. The synopsis for this book drew me in and the story kept me guessing/entertained. While I really enjoyed the audio I felt like maybe there were too many characters to easily follow along.

“What I know for sure is that Mad Dog is not your garden variety sociopath, and this is not Killer 101. Anyone who thinks so is not reading these details right.”


Thanks to NetGalley and the publisher for an arc copy of this. I was intrigued by the synopsis (FBI unit of misfit riddle solvers takes on a case of a serial killer targeting other serial killers), and I’m happy to say this lived up to my expectations.

Firstly, the characters were so good. The protagonist has an eidetic memory and has trouble relating to others. His team comprises of a sharp shooter, a rookie, his always put together boss, and another riddle solver. His relationship with his mom and daughter was touching.

The plot has everything you could want from a serial killer book: ties to a past case, creative murders, cat and mouse games, creepy clues left by the killer in gory places, political intrigue, the case slowly becoming personal.

This is one of the best mystery thrillers I’ve read in a long while, and I am excited to read the next book in the series coming out next year.

Special thanks to the author & @minotaur_books for my gifted copy‼️

A serial killer killing serial killer’s count me in. A team full of FBI misfits we’ll call them triple X ban together to find a serial killer. Each agent specializes in something that will help them find a break in the case. Dropping cryptic messages and hacking the FBI’s database the killer “Mad Dog” sends the team on a wild goose chase that would lead them right back to the Bureau.

This was a cool book filled with dark themes and graphic scenes. It dragged a lot in the beginning and middle but I think I really enjoyed it because it reminded me of the movie The Little Things with a mix of Law & Order. This one might not be for everyone but if you like crime fiction/murder mystery you’ll like this book.

Rating: 3.5/5 ⭐️

This book was fabulous! My first 5 star read of the year. And a bonus of finding a new to me author! I’ve already ordered The Good Detective from the author’s other series!
This thriller was well done. It had me involved right from the start. I loved all the main characters and was invested in their final outcomes. I’m so looking forward to the next book in this wonderful series.

Thanks so much to NetGalley and St Martin’s Press.

This was a solid procedural and i think fans of this genre will enjoy it more than i did - it was a little too plot focused for me, we’re introduced to a lot of characters as it’s the first in a series but it felt like everyone besides Camden was introduced and then put to the side, I found it hard to remember certain characters and how they connected which made the ultimate reveal a little unsatisfying for me. Readers more used to this type of story will enjoy it more than I did, it’s definitely a solidly written serial killer mystery, I just personally found it hard to get super invested.

Head Cases - John McMahon

A fast paced criminal thriller as a group of outcast FBi agents hunts for a serial killer who is killing other serial killers and leading these specific agents on a puzzling chase to stay one step ahead of him.

What happens when you’re an outcast FBI agent? You’re assigned to the PARS unit to connect and hopefully solve cold cases through pattern recognition. Gardner Camden has a perfect memory recall and is particularly good at solving puzzles, unfortunately he also struggles with social skills. Agent Camden does not evoke emotions like others and often finds himself the butt of the joke or shunned because of his demeanor. He, along with a team of other misfit agents, form a found family bond as they work to catch a killer that appears to be sending them a message.

Head Cases read as though the script for Mind Hunters and House MD became one. I really connected with the characters and found myself trying to solve all the mysteries alongside Agent Camden and his colleagues. The ending wasn’t necessarily predictable but it also didn’t blow my mind. Regardless I had a fun time with this one and found myself speeding through to find out what happens next.

Thank you to St. Martin’s Press and NetGalley for my copy; all opinions are my own.

I love a good cat-and-mouse chase! This book was clever, complex, dark, and interesting. I loved the detail that went into this procedural and its characters. Readers who like Criminal Minds will enjoy this book.

This is a great start to an anticipated ongoing series about the PAR unit of the FBI. I really enjoyed John McMahon's characters and I am very excited for future installments of this series. This gave the some comfortable feeling as watching shows like The Mentalist or Bones and I think it'll make for a fantastic procedural TV show if it were to be adapted.

Very interesting police procedural. I really liked the concept behind it, the neurodivergent lead, and the locations. Too often I think neurodivergence is presented in extremes, but McMahon’s lighter touch was just right. I am not sure why the rest of the group were considered “head cases”, but presumably future books in the series will elaborate on that. The unifying thing seemed to be that they are all very smart, and I was drawn to want to know more about each of them. The team is the Patterns and Recognition Unit, and they work to solve the tough cases by identifying the criminal and predicting what he will do next. It was an engaging first book to set up a series. I liked the way Gardner’s character was drawn, as a normal person with his own particular traits, and how Gardner’s relationship with his daughter was included to show another facet to him. I am looking forward to the next book!

Thanks to Netgalley and St. Martin’s Press/Minotaur books for an ARC in exchange for a fair review.

FBI agent Gardner Camden is shocked when DNA links a serial killer he thought was dead to a current murder victim. What is going ok on? Is this a copycat? The killer starts to taunt Gardner. He and his team must get to the bottom of what's really happening.

I received a complimentary copy from the publisher and all opinions expressed are mine.

The book follows Gardner who is an incredible genius who is part of the team that is called to solve
cases that no one else can solve. They are called in to solve a murder case committed by a serial killer long presumed dead and to top it off the killer leaves clues and riddles . It was an interesting premise .

I love a good story about the FBI, and Head Cases met all of my expectations. It was an interesting look at the unit known as PAR, where the outcasts of the department are sent. It was a fast-paced book and kept my attention through the whole book. I really enjoyed the characters, and I'm looking forward the next in the series!

Thank you Minotaur Books and NetGalley for the eARC in exchange for my honest review.

This was such a great book! It's a page turner and goes by so fast! I'm very much looking forward to this being a continued series. There is great character building and an original storyline. I'm someone who enjoys puzzles and enjoyed the patterns and puzzles woven into this mystery. The mystery was well thought out and played nicely with the strengths of the quirky cast members making up the PAR Unit. The PAR Unit is here to stay and I'm here to join them on their next case.

Gardner Camden is unique yet unusual in a good way. He may have trouble connecting with you, but give him a case to solve, and he will devise a million ways to solve it. Gardner combines these unique skills with his special group of misfits, like himself, called PAR (Patterns and Recognition Unit), within the FBI. The team is called into action when a serial killer that they deemed dead seven years ago is recently found the same way he murdered his victims. From that point on, the reader is taken on a journey to find a serial killer killing serial killers and leaving clues that only his unit can solve. Will Gardner and his team catch this killer before the killer gets a chance to reveal his true agenda?

Honestly, I didn’t know what to expect from this book. Before I read a book, I research and try to get a glimpse of what I am about to get myself into. I could not tell if this would be a true crime story based on actual events or if it would mimic some of my favorite crime shows. I was surprised and on the edge of my seat reading this book. This book was thrilling! The author knew how to keep me engaged and entertained! I stayed up late to finish this, and I read the book every chance I could! I am new to John McMahon, but I will research to see what other good reads he has up his sleeve. This book is for you if you like psychological, suspenseful thrillers or hit shows like Criminal Minds, Dexter, or FBI!

FBI Agent Gardner Camden works for the Patterns and Recognition (PAR) unit, whose specialty is solving cold cases. I instantly liked Camden and his crew. They are a nerdy, specialized bunch who see things that others have missed. I appreciate the way their minds work and I thoroughly enjoyed being right there with the team picking up on the clues the killer is leaving for them. He wants to be found. He wants to play. For me this book had a slight Silence of the Lambs feel to it, and I couldn't read fast enough. I wanted the PAR team to find the killer and bring him down, and I was thrilled and in awe every time they found the smallest of clues that propelled the investigation forward. When I reached the end of the book I hoped John McMahon would consider a sequel, so imagine my surprise when I checked Goodreads and found 'PAR Unit, #1' beside the book's title. I am very much looking forward to solving more cases with Agent Camden's extremely literal mind! If you are a sucker for FBI/police procedural stories then this book is for you!

Thank you NetGalley and St. Martin's Press for the DRC in exchange for my honest review.

Great story that I couldn’t put down! I loved seeing the inner workings of the FBI and the main character, Gardner, was so interesting to follow. I hope for more books following the PAR crew

This seems like a fantastic start to this series. Criminal minds vibes here for this book. The characters are interesting and I look forward to more .

This is intense and thrilling read for fans of FBI procedurals. If you're looking for detailed descriptions on how to catch a killer, this book is great. I loved the character development and following along as the PAR unit put the pieces together in their case.

I'm looking forward to reading more with the PAR team.

Thank you NetGalley and publisher for a digital ARC of this book.

Intricate detailed plot of an investigative unit that I have never heard of, PAR. Every person on this unit has a story, but I wish the book was told from a singular point of view instead of multiple. While I appreciate the backstory of each of the characters, it tended to weigh down the plot for me. But overall a solid story with plenty of gory details.