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Betrayal of Trust: A Medical Thriller
Who’s killing the cancer researchers?
A leading clinical investigator is butchered in his hotel room hours after receiving a prestigious award for cancer research. Weeks later, a second researcher is the victim of an apparently random mugging in a parking garage. Unexpectedly, crime scene DNA establishes that the two men were killed by the same woman. But her identity remains unknown, her motive is mysterious, and the connections between the victims are scant—except that they were both collaborating with Professor Brad Parker at the Maine Translational Research Institute. When the killer strikes close to home, Brad and his fiancée—state police lieutenant Karen Richmond—are drawn into a nightmare of maniacal revenge. Until Brad sets a trap for the killer…or falls prey to a trap the killer has set for him.
A leading clinical investigator is butchered in his hotel room hours after receiving a prestigious award for cancer research. Weeks later, a second researcher is the victim of an apparently random mugging in a parking garage. Unexpectedly, crime scene DNA establishes that the two men were killed by the same woman. But her identity remains unknown, her motive is mysterious, and the connections between the victims are scant—except that they were both collaborating with Professor Brad Parker at the Maine Translational Research Institute. When the killer strikes close to home, Brad and his fiancée—state police lieutenant Karen Richmond—are drawn into a nightmare of maniacal revenge. Until Brad sets a trap for the killer…or falls prey to a trap the killer has set for him.
246 pages, Kindle Edition
Published October 7, 2025
24 people are currently reading
1129 people want to read
About the author
Geoffrey M. Cooper
29 books139 followersGeoffrey M. Cooper is an award-winning author of medical thrillers and a 2023 Maine Literary Award Finalist in Crime Fiction. His experience as a former cancer researcher and scientific administrator, having held positions at Harvard Medical School and Boston University as professor, department chair, and associate dean, now provides extensive background for his novels. He lives in Ogunquit, Maine.
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Displaying 1 - 24 of 24 reviews
September 14, 2025
Could not put it down!
This book was fast paced but the story was unveiled in the right components that made you think you knew and then question it. I had the ultimate killer on my list of suspects but kept discounting it.
I love watching crime dramas on TV and this could have easily been a great episode. I’m going to have to go find other books in the series because I would absolutely read another one.
I received the ARC ebook free through The Niche Reader.
This book was fast paced but the story was unveiled in the right components that made you think you knew and then question it. I had the ultimate killer on my list of suspects but kept discounting it.
I love watching crime dramas on TV and this could have easily been a great episode. I’m going to have to go find other books in the series because I would absolutely read another one.
I received the ARC ebook free through The Niche Reader.
August 30, 2025
In the newest Brad Parker and Karen Richmond novel, a mysterious woman with a bevy of tricks up her sleeve starts leaving a bloody trail through the halls of academia. She's smart. She's measured. She's on a revenge mission. That makes Parker and Richmond's hunt for her all the more fun and suspenseful.
As always, Cooper's smooth prose carries the thrilling plot expertly through to its climax, making for a real page-turner. The setting of Maine is an added bonus, with all the uniqueness that state has to offer. It's a wonderful installment to the series!
(I received an advanced reading copy of this book.)
As always, Cooper's smooth prose carries the thrilling plot expertly through to its climax, making for a real page-turner. The setting of Maine is an added bonus, with all the uniqueness that state has to offer. It's a wonderful installment to the series!
(I received an advanced reading copy of this book.)
October 9, 2025
Betrayal of trust
I’m gonna start out by saying the medical jargon goes right over my head. However that does not take away from how good the story is. I’m not sure how fact based drugs like these are but goodness knows the world could use a cure for the horrible disease that is cancer. The mystery itself is confounding for the reader and the detectives investigating. I will say at one point I was absolutely certain that I knew who the killer was only to be shocked when the true culprit was revealed. It was amazing in an eerie way how these crimes were planned and executed but given the profession of the perpetrator it kinda makes sense in a twisted way. This is definitely a story that makes you think but it’s also relatable because I don’t think anyone can go through life without being touched by this disease in some way. Great premise, superb plot and one doozy of a surprise killer.
I’m gonna start out by saying the medical jargon goes right over my head. However that does not take away from how good the story is. I’m not sure how fact based drugs like these are but goodness knows the world could use a cure for the horrible disease that is cancer. The mystery itself is confounding for the reader and the detectives investigating. I will say at one point I was absolutely certain that I knew who the killer was only to be shocked when the true culprit was revealed. It was amazing in an eerie way how these crimes were planned and executed but given the profession of the perpetrator it kinda makes sense in a twisted way. This is definitely a story that makes you think but it’s also relatable because I don’t think anyone can go through life without being touched by this disease in some way. Great premise, superb plot and one doozy of a surprise killer.
October 3, 2025
I received an ARC of this book by "The Niche Reader" for an honest review.
This is a medical thriller by Geoffrey M Cooper. Brad is a Professor at a research institute. Brad is supposed to meet a clinical investigator to discuss a clinical trial for a patient, but before he can do that, the investigator is killed. Then another investigator is murdered. The police, including Brad's fiance, starts investigating. They discover the killer is closer to Brad than he thinks. Intricate plot, many twists, and overall a great, fast paced story. Would recommend.
This is a medical thriller by Geoffrey M Cooper. Brad is a Professor at a research institute. Brad is supposed to meet a clinical investigator to discuss a clinical trial for a patient, but before he can do that, the investigator is killed. Then another investigator is murdered. The police, including Brad's fiance, starts investigating. They discover the killer is closer to Brad than he thinks. Intricate plot, many twists, and overall a great, fast paced story. Would recommend.
September 14, 2025
Geoffrey M. Cooper's Betrayal of Trust sets its sights on the shadowy intersections of science, power, and morality, delivering a story that is as intellectually gripping as it is emotionally charged. It opens with a fiery hook and from that moment, the novel grips you with a potent mix of scientific intrigue, psychological drama, and the high stakes of justice gone personal.
The novel dives into the murky underbelly of academic medicine, exposing how power, reputation, and predation intertwine. As the story progresses, the author does a great job of raising the stakes from personal revenge to systemic rot. Author Cooper’s background in science lends the novel a razor-sharp authenticity. From clinical trial data to DNA evidence, the details never feel forced, but rather elevate the story’s stakes.
Brad Parker is an excellent protagonist and Shirley makes for a fascinating antagonist; she is morally complex, technically skilled, and driven by both revenge and justice. The interplay between Brad Parker and Karen Richmond is one of the book’s greatest strengths. Their combined expertise, science and law enforcement, creates a dynamic that’s both intellectual and emotional.
While I thoroughly enjoyed the book, there are moments where the narrative could have been tighter. Surveillance details and hacking logistics, while realistic, occasionally slowed the pace. Additionally, some of the secondary characters could have been fleshed out more deeply to add layers of emotional resonance. These are, however, just minor issues compared to the overall experience of reading this book.
Betrayal of Trust is a tense and timely thriller that explores what happens when power, science, and exploitation collide. Author Cooper balances ethical questions with a strong, suspenseful narrative, making this one of the more thought-provoking medical thrillers I’ve read recently. If you enjoy Robin Cook or Michael Palmer, this book deserves a spot on your shelf.
The novel dives into the murky underbelly of academic medicine, exposing how power, reputation, and predation intertwine. As the story progresses, the author does a great job of raising the stakes from personal revenge to systemic rot. Author Cooper’s background in science lends the novel a razor-sharp authenticity. From clinical trial data to DNA evidence, the details never feel forced, but rather elevate the story’s stakes.
Brad Parker is an excellent protagonist and Shirley makes for a fascinating antagonist; she is morally complex, technically skilled, and driven by both revenge and justice. The interplay between Brad Parker and Karen Richmond is one of the book’s greatest strengths. Their combined expertise, science and law enforcement, creates a dynamic that’s both intellectual and emotional.
While I thoroughly enjoyed the book, there are moments where the narrative could have been tighter. Surveillance details and hacking logistics, while realistic, occasionally slowed the pace. Additionally, some of the secondary characters could have been fleshed out more deeply to add layers of emotional resonance. These are, however, just minor issues compared to the overall experience of reading this book.
Betrayal of Trust is a tense and timely thriller that explores what happens when power, science, and exploitation collide. Author Cooper balances ethical questions with a strong, suspenseful narrative, making this one of the more thought-provoking medical thrillers I’ve read recently. If you enjoy Robin Cook or Michael Palmer, this book deserves a spot on your shelf.
September 19, 2025
I received an ARC through "Booksirens" and I am voluntarily leaving an honest review.
The story begins with the murder of a cancer doctor in Boston whom Brad was to meet with the next morning to discuss that person handling a cancer trial for a new discovery. Before Brad is able to have his meeting, he has someone knocking on his hotel room door where he learns that doctor has been murdered. Karen had also arrived and she and Brad had worked previously with Zelden, the detective at their door.
Brad on returning back in Maine had to try and locate someone else that would be able to handle the caner trials for what his teams had discovered. He was lucky and discovered another doctor in Portland that would be able to handle both groups. After Brad and Carolyn met with Steve Lowell, the doctor in Portland, Lowell was murdered and it was later discovered that the killer was the same person that had killed Eric Salton, the doctor in Boston. After this happened, and because their work with Lowell had reached a certain point, they determined that they could handle the trials themselves and Carolyn would be the lead. As a result of this decision, Carolyn then became a target of the killer.
After Brad determined that the killer was someone within his own organization and put a plan to flush and capture the killer. To discover what Brad's plan was, who the killer was, what the reason for the killings and how it all worked out in the end, then you must read this book, you won't be disappointed!
The story begins with the murder of a cancer doctor in Boston whom Brad was to meet with the next morning to discuss that person handling a cancer trial for a new discovery. Before Brad is able to have his meeting, he has someone knocking on his hotel room door where he learns that doctor has been murdered. Karen had also arrived and she and Brad had worked previously with Zelden, the detective at their door.
Brad on returning back in Maine had to try and locate someone else that would be able to handle the caner trials for what his teams had discovered. He was lucky and discovered another doctor in Portland that would be able to handle both groups. After Brad and Carolyn met with Steve Lowell, the doctor in Portland, Lowell was murdered and it was later discovered that the killer was the same person that had killed Eric Salton, the doctor in Boston. After this happened, and because their work with Lowell had reached a certain point, they determined that they could handle the trials themselves and Carolyn would be the lead. As a result of this decision, Carolyn then became a target of the killer.
After Brad determined that the killer was someone within his own organization and put a plan to flush and capture the killer. To discover what Brad's plan was, who the killer was, what the reason for the killings and how it all worked out in the end, then you must read this book, you won't be disappointed!
September 14, 2025
What’s better than a Brad and Karen thriller from Geoffrey Cooper? A Brad and Karen and Martin Dawson thriller! If you read earlier books in the series, you know him as the soldier-turned-medical-researcher who is a good friend of Brad, and who has helped the duo out in the past. I always enjoy his scenes, and so I was delighted when he teamed up with them again, assuming he would once again heroically help them all work as a team to catch the killer, as he’s done before.
Well, the way it all works out in this book is a little different. But I can’t say how. Sorry, you’ll just have to read it. What I can say is that the book is about a mysterious killer who keeps striking important medical researchers. Brad and Karen’s theories regarding her motives are forced to evolve with each crime, until eventually the pattern emerges in an unsettling way.
But what I think I liked best of all about this book is what the title refers to. The betrayal in question could be multiple things, including one possibility that isn’t even connected directly to the killer. I like ambiguity and mystery, leaving things up to interpretation. All in all, exactly the sort of enjoyable mystery fans of the series have come to expect.
Well, the way it all works out in this book is a little different. But I can’t say how. Sorry, you’ll just have to read it. What I can say is that the book is about a mysterious killer who keeps striking important medical researchers. Brad and Karen’s theories regarding her motives are forced to evolve with each crime, until eventually the pattern emerges in an unsettling way.
But what I think I liked best of all about this book is what the title refers to. The betrayal in question could be multiple things, including one possibility that isn’t even connected directly to the killer. I like ambiguity and mystery, leaving things up to interpretation. All in all, exactly the sort of enjoyable mystery fans of the series have come to expect.
December 17, 2025
I received this book for free as a Goodreads giveaway.
A hook-up gone wrong, a parking garage mugging, and a botched home invasion. Two people are dead. What connects the three crimes?
The victims are all cancer researchers.
The first victim was known to destroy the careers of women who rejected his advances, so the investigation starts by looking at his victims, but the detectives can never quite connect the dots, and start to look elsewhere. But the detectives aren’t really the main characters - the “hero” is Brad, the director of a research institute, whose girlfriend Karen is herself a detective, who starts to unravel the tangled story.
This was fine. The plot hinges on the accepted method for testing new drugs, and a lot of information is sort of awkwardly explained to the reader by having it to some graduate students (who should really already know this stuff!). It felt a little all over the place, with Brad, Karen, Zelen, and who knows how many other people involved in the investigation. And while I understand the killer’s motivation, they should totally have understood the drug trial process well enough to realize the risk. And for Karen to say that Salton deserved to die? That was a little “ick.”
A hook-up gone wrong, a parking garage mugging, and a botched home invasion. Two people are dead. What connects the three crimes?
The victims are all cancer researchers.
The first victim was known to destroy the careers of women who rejected his advances, so the investigation starts by looking at his victims, but the detectives can never quite connect the dots, and start to look elsewhere. But the detectives aren’t really the main characters - the “hero” is Brad, the director of a research institute, whose girlfriend Karen is herself a detective, who starts to unravel the tangled story.
This was fine. The plot hinges on the accepted method for testing new drugs, and a lot of information is sort of awkwardly explained to the reader by having it to some graduate students (who should really already know this stuff!). It felt a little all over the place, with Brad, Karen, Zelen, and who knows how many other people involved in the investigation. And while I understand the killer’s motivation, they should totally have understood the drug trial process well enough to realize the risk. And for Karen to say that Salton deserved to die? That was a little “ick.”
October 5, 2025
I enjoy this series and like the fact that this husband-wife team, Brad Parker and Karen Richmond, have such different careers yet seem to be able to work together so well when working on solving a crime. And the crimes they work on are not ordinary events, each book presents an involved academic problem and brings in Karen's expertise and resources very thoroughly. After all of the murders that they worked on together, it seems that Brad is still clueless as to how much help Karen can be, and how she would understand how to help without revealing all of the cards. Male ego perhaps? He can do it all himself? I find this very frustrating but it's probably one of the situations introduced to keep the tension high. In this book, the killer was obvious to me fairly quickly and although I hadn't completely guessed the motive, it was clear who would be to blame. Nevertheless, I love to read these thrillers and am anxious to see the next one.
This ARC was provided by BookSirens and the publisher, the opinions expressed herein are strictly my own.
This ARC was provided by BookSirens and the publisher, the opinions expressed herein are strictly my own.
October 4, 2025
Another great addition to the Brad Parker and Karen Richmond series. I enjoy reading these books in part because they're just the right amount of suspense and intrigue for me and won't keep me up at night! The medical aspect of the story fascinates me and the author delivers the information in such a way that it's not too technical, but it isn't really 'dumbed-down' either. I enjoy the writing style, the book is well paced, and I look forward to picking up where I left off each day. If you haven't read any other books in the series, you'll still be able to follow the story and there are just the right amount of references to previous experiences that you'll be able to figure out relationships reasonably easily.
Thanks to BookSirens, the publisher and the author for a complimentary arc. All opinions are my own and my review is left voluntarily.
Thanks to BookSirens, the publisher and the author for a complimentary arc. All opinions are my own and my review is left voluntarily.
October 11, 2025
This book follows Professor Brad Parker, a clinical investigator whose life spirals into chaos when a colleague is brutally murdered just after receiving a prestigious cancer research award. The tension escalates when a second researcher is killed in an apparent mugging, and DNA evidence reveals both victims were murdered by the same mysterious woman. As Brad and his fiancée, state police lieutenant Karen Richmond, delve into the investigation, they uncover a web of betrayal linked to their professional lives. With the killer striking closer to home, Brad must navigate trust and deception as he sets a trap for the killer, all while facing the haunting consequences of ambition and revenge.
This gripping medical thriller blends suspense with an ethical dilemma.
I would have given it 5 stars, except I figured out the killer in the first half of the book.
This gripping medical thriller blends suspense with an ethical dilemma.
I would have given it 5 stars, except I figured out the killer in the first half of the book.
September 1, 2025
I love this series. The medical stuff mostly goes over my head, but they all have interesting stories and great twists.
Also, I love the New England aesthetic. I lived there for three years and absolutely love the area the author describes in this series. Also, these books make me so hungry. The characters always have these delicious meals, and I get super jealous of them. I will continue to read this series. As said above, the storylines are always good. The twists and suspense keep you on the cliff, and the character dynamics are great, too.
I received an advance review copy for free, and I am leaving this review voluntarily
Also, I love the New England aesthetic. I lived there for three years and absolutely love the area the author describes in this series. Also, these books make me so hungry. The characters always have these delicious meals, and I get super jealous of them. I will continue to read this series. As said above, the storylines are always good. The twists and suspense keep you on the cliff, and the character dynamics are great, too.
I received an advance review copy for free, and I am leaving this review voluntarily
September 24, 2025
This is another riveting read in this series. There's a lot of medical stuff there that to be honest, goes over my head, but it doesn't make any difference. It actually makes the story more intriguing.
This starts off with the murder of a man just after he has received an award for cancer research. Another killing provides an unexpected connection and brings Brad and Karen further into the investigation. I raced through this as usual. It's so easy to read and the food here made me salivate all the way through. I liked how the story flowed to its conclusion. This time I particularly enjoyed the empathy shown after the first killing. It made the character feel more human.
I received an advance review copy for free, and I am leaving this review voluntarily.
This starts off with the murder of a man just after he has received an award for cancer research. Another killing provides an unexpected connection and brings Brad and Karen further into the investigation. I raced through this as usual. It's so easy to read and the food here made me salivate all the way through. I liked how the story flowed to its conclusion. This time I particularly enjoyed the empathy shown after the first killing. It made the character feel more human.
I received an advance review copy for free, and I am leaving this review voluntarily.
August 13, 2025
I've read several now in this series, and they've all been page turners.
Each is well written with relatable and believable rounded characters as well as a plot with plenty of twists and turns.
Without sharing the plot details, I enjoyed the fact that one of the leading characters felt empathy when investigating the first murder, which was rapidly put into the shade by the subsequent events.
Hopefully this series will continue with several more books yet…
I received an advance review copy for free, and I am leaving this review voluntarily.
Each is well written with relatable and believable rounded characters as well as a plot with plenty of twists and turns.
Without sharing the plot details, I enjoyed the fact that one of the leading characters felt empathy when investigating the first murder, which was rapidly put into the shade by the subsequent events.
Hopefully this series will continue with several more books yet…
I received an advance review copy for free, and I am leaving this review voluntarily.
August 25, 2025
By far, one of my favorite series, this is a medical research mystery series. Being set in southern Maine, is one of the attractions as I am from NH. I love the name-dropping of places that I have been to. But more importantly, these books are extremely well written, have great character development, and have lots of twists and turns. The author also does an excellent job explaining the more technical parts of the story-line. I think this series is a must read. Thanks to BookSirens for the ARC of this book.
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November 26, 2025Betrayal of Trust is a sharp, fast moving medical thriller that hooks you with tension from the first chapter and never really lets up. The blend of cutting edge cancer research, hidden motives, and escalating danger creates a story where every discovery feels like it could be the one that blows everything open or pulls the characters deeper into a trap. The pacing is tight, the stakes feel real, and the mix of science and suspense gives the plot an extra layer of intensity. Fans of smart, high pressure thrillers will find plenty to sink into here.
September 9, 2025
True to Geoffrey Cooper's writing style, the book flows smoothly and at a quick pace. I was kept entertained and read it within one day. I enjoyed the storyline. The rollercoaster ride of people's careers and lives at peril are a true hallmark of his writing. As is his exquisite taste in seafood, birds, and scotch.
October 13, 2025
This is a chilling thriller. I enjoyed the dual viewpoint. I had a niggling suspicion as to who the murderer was but wasn’t convinced I had it right. It was a well thought out spree and there were many details that were planned for. I also didn’t pick up on the connection between the victims until the story revealed it. Well written and enthralling! I greatly enjoyed it!
September 24, 2025
⭐️⭐️⭐️
Most of the book moved at a slower pace, which made it harder to stay fully engaged. However, the ending really delivered—I loved how it all came together and thought the conclusion was strong.
Most of the book moved at a slower pace, which made it harder to stay fully engaged. However, the ending really delivered—I loved how it all came together and thought the conclusion was strong.
September 29, 2025
I could not put it down! Intriguing with well-developed characters and storyline. The murders and tracking of the suspect who was killing the clinical trials' directors was so interesting and the twists kept me guessing until the end.
December 13, 2025
WOW! This book was gripping from the very first page, from the very first word even, and it kept me engaged until the very last. Very well written, with lots of twists and turns, I couldn't put it down. I will be reading the rest of the books in this series and others by this author.
October 8, 2025
Great quick thriller! I need to go back to the beginning and read them all! Really enjoyed the story!
October 31, 2025
He did it again
Another murder mystery that is filled with twists and turns. The dynamic duo compliment each other and make this another interesting page turner.
Another murder mystery that is filled with twists and turns. The dynamic duo compliment each other and make this another interesting page turner.
November 5, 2025
This was an interesting, fast read. The characters were well developed and the plot held my interest.
Thanks for the free book.
Thanks for the free book.
Displaying 1 - 24 of 24 reviews