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Kat and Lock #3
Human Remains
From the author of In the Blink of an Eye, the Sunday Times bestseller, winner of the CWA ILP John Creasey (New Blood) Dagger and Theakston Old Peculier Crime Novel of the Year.
DCS Kat Frank and AIDE Lock are back in a cutting-edge new thriller.
The truth will always come out, but at what cost?
Fresh from successfully closing their first live case, the Future Policing Unit are called in to investigate when a headless, handless body is found on a Warwickshire farm. But as they work to identify the victim and their killer, the discovery of a second body begins to spark fears that The Aston Strangler is back. And as the stakes rise for the team, so do the tensions brewing within it.
When DCS Kat Frank is accused of putting the wrong man behind bars all those years ago, AIDE Lock – the world's first AI Detective – pursues the truth about what happened with relentless logic. But Kat is determined to keep the past buried, and when she becomes the target of a shadowy figure looking for revenge, Lock is torn between his evidence-based algorithms and the judgement of his partner, with explosive results.
When everything hangs in the balance, it will all come down to just how much an AI machine can learn, and what happens when they do . . .
DCS Kat Frank and AIDE Lock are back in a cutting-edge new thriller.
The truth will always come out, but at what cost?
Fresh from successfully closing their first live case, the Future Policing Unit are called in to investigate when a headless, handless body is found on a Warwickshire farm. But as they work to identify the victim and their killer, the discovery of a second body begins to spark fears that The Aston Strangler is back. And as the stakes rise for the team, so do the tensions brewing within it.
When DCS Kat Frank is accused of putting the wrong man behind bars all those years ago, AIDE Lock – the world's first AI Detective – pursues the truth about what happened with relentless logic. But Kat is determined to keep the past buried, and when she becomes the target of a shadowy figure looking for revenge, Lock is torn between his evidence-based algorithms and the judgement of his partner, with explosive results.
When everything hangs in the balance, it will all come down to just how much an AI machine can learn, and what happens when they do . . .
384 pages, Kindle Edition
First published April 24, 2025
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Displaying 1 - 30 of 428 reviews
April 25, 2025
My crime reads are far between, as I grew tired of gore and police investigations, but this series is an exception. As the previous books AI is used to help the police, and I love the questions it raises and the dilemmas we are facing in the future. I must also say that the author does a great job in getting into people’s heads, and even if I found the main character a bit annoying due to her very defensive style, it was a trait she never wavered from and it was also questioned. Overall a great and different crime novel.
January 3, 2026
I don’t use Goodreads anymore but had to come on and hype this book up.
My favourite thriller book series ever.
My favourite thriller book series ever.
July 28, 2025
The twists in ‘Human Remains’ completely floored me – I honestly couldn’t believe what I was reading. I need book four immediately.
It’s been four months since the ‘Coventry Crucifier’ case (from Leave No Trace) was wrapped up, when a fisherman discovers a headless, handless human body buried in a local riverbank – remains estimated to be a year old.
Meanwhile, DCS Kat Frank is under renewed scrutiny as a true crime podcast re-examines her first big case, the ‘Ashton Strangler’ – suggesting she put the wrong man behind bars and the real killer is still out there. Social media erupts with hashtags like #bentbitch, fanning the flames of public suspicion.
As if that weren’t enough, someone is watching Kat. Lurking outside her home – seething with rage, and plotting revenge.
Kat, her AI partner AIDE Lock, and the rest of her team are thrown into a deeply personal and dangerous investigation that tests every boundary.
Those twists! OMG. I’m so glad I stuck with this series. As you know, I wasn’t overly taken with Leave No Trace, but this entry totally won me back. If you felt the same way, I strongly encourage you to give this one a shot – you won’t regret it. Speaking of regrets, perhaps my rating for the second instalment was too harsh, given that so much of what occurred in that one, made the amazingness of this one possible, however… Anyway, this was hands-down my favourite in the series so far, and I honestly don’t know how I’ll cope waiting for book four.
I also was relieved that the story returned to a cold case, just like in book one (In the Blink of An Eye), which I much preferred over the live-case approach in book two. Definitely read these in order, though – the emotional impact of the twists depends on it.
Love was a recurring theme throughout this book. Romance continued to bloom between DI Rayan Hassan and Professor Adaiba Okonedo (Lock’s creator), while Kat’s son Cameron brought home his first serious girlfriend from university to introduce to his mum. The cold case also revolved around lost love and familial love. Even DS Debbie Browne, now on maternity leave, radiated a new kind of devotion toward her baby girl, Lottie.
And then there was Kat and Lock. They shared a few tender, almost intimate moments that really caught me off guard. I even found myself (briefly!) imagining them as a couple, before quickly reminding myself that Lock is, after all, just code. Fascinating, empathetic code… but still!
There’s so much more I could say, but the rest veers into spoiler territory. Just know this: at least three of the twists in Human Remains were among the most memorable and shocking I’ve ever read. I’m still reeling. You’d better be writing right now Jo Callaghan.
An absolute standout! Human Remains is definitely a top contender for my end-of-year favourites.
It’s been four months since the ‘Coventry Crucifier’ case (from Leave No Trace) was wrapped up, when a fisherman discovers a headless, handless human body buried in a local riverbank – remains estimated to be a year old.
Meanwhile, DCS Kat Frank is under renewed scrutiny as a true crime podcast re-examines her first big case, the ‘Ashton Strangler’ – suggesting she put the wrong man behind bars and the real killer is still out there. Social media erupts with hashtags like #bentbitch, fanning the flames of public suspicion.
As if that weren’t enough, someone is watching Kat. Lurking outside her home – seething with rage, and plotting revenge.
Kat, her AI partner AIDE Lock, and the rest of her team are thrown into a deeply personal and dangerous investigation that tests every boundary.
Those twists! OMG. I’m so glad I stuck with this series. As you know, I wasn’t overly taken with Leave No Trace, but this entry totally won me back. If you felt the same way, I strongly encourage you to give this one a shot – you won’t regret it. Speaking of regrets, perhaps my rating for the second instalment was too harsh, given that so much of what occurred in that one, made the amazingness of this one possible, however… Anyway, this was hands-down my favourite in the series so far, and I honestly don’t know how I’ll cope waiting for book four.
I also was relieved that the story returned to a cold case, just like in book one (In the Blink of An Eye), which I much preferred over the live-case approach in book two. Definitely read these in order, though – the emotional impact of the twists depends on it.
Love was a recurring theme throughout this book. Romance continued to bloom between DI Rayan Hassan and Professor Adaiba Okonedo (Lock’s creator), while Kat’s son Cameron brought home his first serious girlfriend from university to introduce to his mum. The cold case also revolved around lost love and familial love. Even DS Debbie Browne, now on maternity leave, radiated a new kind of devotion toward her baby girl, Lottie.
And then there was Kat and Lock. They shared a few tender, almost intimate moments that really caught me off guard. I even found myself (briefly!) imagining them as a couple, before quickly reminding myself that Lock is, after all, just code. Fascinating, empathetic code… but still!
There’s so much more I could say, but the rest veers into spoiler territory. Just know this: at least three of the twists in Human Remains were among the most memorable and shocking I’ve ever read. I’m still reeling. You’d better be writing right now Jo Callaghan.
An absolute standout! Human Remains is definitely a top contender for my end-of-year favourites.
May 18, 2025
*Costly Truth*
**4.5 Stars**
This is the third book in the “Kat and Lock” series. In this instalment, DCS Kat Frank collaborates with AI creation Aide Lock to assist the police in navigating complex jargon and expediting investigations. Lock’s exceptional abilities include quickly analysing statistics and generating answers in minutes that would take a human days to compile. Additionally, he is actively learning and understanding human behaviour.
Following their successful first live case, Kat and Lock are immediately thrust into another grim case. A body is discovered on a farm, and at the same time, the son of a past case that significantly contributed to Kat’s career emerges, casting doubt on the verdict.
Unbeknownst to Kat, the son has begun a podcast to undermine her credibility and suggest that she may not have apprehended the correct perpetrator. Despite this growing threat, Kat remains focussed on solving the current case, determined to ignore the leaks of information.
As the investigation progresses, a second body is found on the farm, leading Kat to suspect a specific individual. Just as she believes she has finally solved the case, the podcast gains traction, and Kat realises the devastating consequences of an omission she made. This oversight will have unforeseen repercussions, affecting multiple lives.
When her life is in danger, Lock is unable to assist her without a body. As a machine, he is forced to make a judgment that results in a catastrophic explosion with irreversible effects.
This pivotal moment prompts Kat to question Lock’s actions and motives. The outcome will grant him something he desires, but the high cost of it makes her wonder if machines can possess genuine motivations. The incident also sent a shiver down my spine.
**4.5 Stars**
This is the third book in the “Kat and Lock” series. In this instalment, DCS Kat Frank collaborates with AI creation Aide Lock to assist the police in navigating complex jargon and expediting investigations. Lock’s exceptional abilities include quickly analysing statistics and generating answers in minutes that would take a human days to compile. Additionally, he is actively learning and understanding human behaviour.
Following their successful first live case, Kat and Lock are immediately thrust into another grim case. A body is discovered on a farm, and at the same time, the son of a past case that significantly contributed to Kat’s career emerges, casting doubt on the verdict.
Unbeknownst to Kat, the son has begun a podcast to undermine her credibility and suggest that she may not have apprehended the correct perpetrator. Despite this growing threat, Kat remains focussed on solving the current case, determined to ignore the leaks of information.
As the investigation progresses, a second body is found on the farm, leading Kat to suspect a specific individual. Just as she believes she has finally solved the case, the podcast gains traction, and Kat realises the devastating consequences of an omission she made. This oversight will have unforeseen repercussions, affecting multiple lives.
When her life is in danger, Lock is unable to assist her without a body. As a machine, he is forced to make a judgment that results in a catastrophic explosion with irreversible effects.
This pivotal moment prompts Kat to question Lock’s actions and motives. The outcome will grant him something he desires, but the high cost of it makes her wonder if machines can possess genuine motivations. The incident also sent a shiver down my spine.
August 25, 2026
Human Remains by Jo Callaghan
Synopsis /
The truth will always come out, but at what cost?
Fresh from successfully closing their first live case, the Future Policing Unit are called in to investigate when a headless, handless body is found on a Warwickshire farm. But as they work to identify the victim and their killer, the discovery of a second body begins to spark fears that The Aston Strangler is back. And as the stakes rise for the team, so do the tensions brewing within it.
When DCS Kat Frank is accused of putting the wrong man behind bars all those years ago, AIDE Lock – the world's first AI Detective – pursues the truth about what happened with relentless logic. But Kat is determined to keep the past buried, and when she becomes the target of a shadowy figure looking for revenge, Lock is torn between his evidence-based algorithms and the judgement of his partner, with explosive results.
My Thoughts /
For those readers who are not familiar with this crime/police procedural series – it's a little left field. It highlights cases worked by the Warwickshire Police Future Policing Unit, which is headed up by DCS Kat Frank and her team. The FPU is a Unit uniquely tasked with testing and integrating machine learning technology—specifically working alongside Artificially Intelligent Detective Entity (or AIDE) Lock—to solve cold and active cases. AIDE Lock is a sophisticated machine-learning hologram capable of processing data and cross-referencing information in seconds and is the creation of Professor Okonedo – a leading scientist and researcher at the National Institute for AI Research. The Institute has partnered with the Warwickshire Police (or more specifically, with the FPU) to pilot the project. Which begs the question – can AI adapt to real-world policing?
With the 2026 World Humanoid Robot Games recently held in Beijing, China (22-26 August) it made this reader think about how far AI has come. It's no longer just an idea in someone's mind, it's now a definite reality. And the growth of AIDE Lock's character, from his inception in the first novel to now, in the third, is, quite frankly, eyebrow raising.
Fresh off their last victory, the Warwickshire Future Policing Unit is called out to a local farm. Upon arriving, the team discover a heavily mutilated, headless, and handless corpse—a deliberate attempt by the killer to erase the victim's identity.
Tasked with mapping geographical anomalies across the Warwickshire area, in the hope of locating the victim's head and hands, AIDE Lock uncovers a second body similarly staged and hidden. The unsettling signature of these two crimes sparks a widespread terror that "The Aston Strangler"—a notorious historical serial killer—has resurfaced. Tensions run high when a public accusation forces Kat to confront her own legacy—she was the arresting officer who put the supposed Strangler behind bars years ago. Does the discovery of these two new victims suggest she may have locked up an innocent man while the real killer walked free? This uncertainty fractures the unit's dynamic.
Jo Callaghan’s writing brilliantly weaponizes her real-world background as a senior AI workplace strategist to construct a layered, thought-provoking procedural that completely avoids standard sci-fi tropes. Her prose seamlessly blends classic, grit-infused British noir with ultra-modern mixed-media framing devices, peppering the central mystery with realistic podcast snippets, social media commentary, and formatted police interviews. Rather than using artificial intelligence as a simple gimmick, the author masterfully uses Lock as an objective mirror with which to expose human flaws, personal biases, and systemic vulnerabilities.
With this series, Callaghan masterfully establishes an addictive narrative tension that is simultaneously an edge-of-your-seat thriller and an elegant, philosophical exploration of what it truly means to be human.
Highly recommended.
Synopsis /
The truth will always come out, but at what cost?
Fresh from successfully closing their first live case, the Future Policing Unit are called in to investigate when a headless, handless body is found on a Warwickshire farm. But as they work to identify the victim and their killer, the discovery of a second body begins to spark fears that The Aston Strangler is back. And as the stakes rise for the team, so do the tensions brewing within it.
When DCS Kat Frank is accused of putting the wrong man behind bars all those years ago, AIDE Lock – the world's first AI Detective – pursues the truth about what happened with relentless logic. But Kat is determined to keep the past buried, and when she becomes the target of a shadowy figure looking for revenge, Lock is torn between his evidence-based algorithms and the judgement of his partner, with explosive results.
My Thoughts /
For those readers who are not familiar with this crime/police procedural series – it's a little left field. It highlights cases worked by the Warwickshire Police Future Policing Unit, which is headed up by DCS Kat Frank and her team. The FPU is a Unit uniquely tasked with testing and integrating machine learning technology—specifically working alongside Artificially Intelligent Detective Entity (or AIDE) Lock—to solve cold and active cases. AIDE Lock is a sophisticated machine-learning hologram capable of processing data and cross-referencing information in seconds and is the creation of Professor Okonedo – a leading scientist and researcher at the National Institute for AI Research. The Institute has partnered with the Warwickshire Police (or more specifically, with the FPU) to pilot the project. Which begs the question – can AI adapt to real-world policing?
With the 2026 World Humanoid Robot Games recently held in Beijing, China (22-26 August) it made this reader think about how far AI has come. It's no longer just an idea in someone's mind, it's now a definite reality. And the growth of AIDE Lock's character, from his inception in the first novel to now, in the third, is, quite frankly, eyebrow raising.
Fresh off their last victory, the Warwickshire Future Policing Unit is called out to a local farm. Upon arriving, the team discover a heavily mutilated, headless, and handless corpse—a deliberate attempt by the killer to erase the victim's identity.
Tasked with mapping geographical anomalies across the Warwickshire area, in the hope of locating the victim's head and hands, AIDE Lock uncovers a second body similarly staged and hidden. The unsettling signature of these two crimes sparks a widespread terror that "The Aston Strangler"—a notorious historical serial killer—has resurfaced. Tensions run high when a public accusation forces Kat to confront her own legacy—she was the arresting officer who put the supposed Strangler behind bars years ago. Does the discovery of these two new victims suggest she may have locked up an innocent man while the real killer walked free? This uncertainty fractures the unit's dynamic.
Jo Callaghan’s writing brilliantly weaponizes her real-world background as a senior AI workplace strategist to construct a layered, thought-provoking procedural that completely avoids standard sci-fi tropes. Her prose seamlessly blends classic, grit-infused British noir with ultra-modern mixed-media framing devices, peppering the central mystery with realistic podcast snippets, social media commentary, and formatted police interviews. Rather than using artificial intelligence as a simple gimmick, the author masterfully uses Lock as an objective mirror with which to expose human flaws, personal biases, and systemic vulnerabilities.
With this series, Callaghan masterfully establishes an addictive narrative tension that is simultaneously an edge-of-your-seat thriller and an elegant, philosophical exploration of what it truly means to be human.
Highly recommended.
November 17, 2025
To me, this was a let down. The overall plot was intriguing, but then there were references to Kat’s first case and soon real threats appeared, and she was just so stubborn, whenever her team questioned her decisions and her priorities, she just said: because I say so. Like a parent telling off annoying children.
I ended up skipping to the end which was actually okay, ending with a real cliffhanger. So maybe the book deserves 3 stars.
I ended up skipping to the end which was actually okay, ending with a real cliffhanger. So maybe the book deserves 3 stars.
June 1, 2025
Oh my days, Jo Callaghan just raised the stakes once more. That book is pure genius. Writing, concept, story, characters, there are no weak points here. Human Remains is a perfect, perfect book.
DCS Kat Frank and AIDE Lock are back and the case that they're faced with is bound to test their relationship to its absolute limits.
I can't even put into words how much I loved that book. The underlying tension, the constant threat, the ethical questions regarding Locke. Jo Callaghan writes with such ease and creates a story that's so thrilling and compelling that you can't help but love it.
And that ending... The questions that I'm left with. Please, I need another Kat and Locke book like right now!
DCS Kat Frank and AIDE Lock are back and the case that they're faced with is bound to test their relationship to its absolute limits.
I can't even put into words how much I loved that book. The underlying tension, the constant threat, the ethical questions regarding Locke. Jo Callaghan writes with such ease and creates a story that's so thrilling and compelling that you can't help but love it.
And that ending... The questions that I'm left with. Please, I need another Kat and Locke book like right now!
May 1, 2025
Brilliant as always! This series just keeps getting better and better. Absolutely loved this one and already dying for book 4
January 13, 2025
This is the third book in the fantastic Kat & Locke series by Jo Callaghan. It was published by Simon & Schuster UK on 24th April 2025. I was lucky enough to read a very early proof copy.
If you haven’t read the first two books, In the Blink of An Eye and Leave No Trace, then STOP reading this review now and go buy the first two books IMMEDIATELY.
This is fast becoming one of my favourite series. If you are still reading this review despite my comments above, I will try to summarise for you.
In The Blink of An Eye (book 1) introduces the reader to DCS Kat Frank. She recently lost her husband and is now a widowed single mother. After his tragic passing, she returned to work as a detective. She is picked to lead a new pilot programme where she is teamed up with an Artificially Intelligent Detective called Lock. It’s basically AI versus human experience and logic versus instinct as Kat and Lock investigate cold cases.
I would strongly recommend that you read the series in order. There are several members of the team you need to get to know. Books 1 and 2 introduce you to everyone in detail, including their back stories.
The latest book, Human Remains starts when a headless, handless body is found buried on a local farm. Kat, Lock and the rest of the team are tasked with finding out who the victim is. There is also a parallel story running as someone is watching Kat and wants revenge at whatever cost.
Kat is also battling her emotions as her only son is now away at University. She is struggling with an empty nest and loneliness. It doesn’t help that one of her team is now on maternity leave and she is feeling threatened because one of her past cases is hitting the headlines for all the wrong reasons.
The lines between AI and friend are beginning to blur. Kat and Lock start to depend upon each other more and more throughout this story.
I’m not going to say much more.. but THAT ending gave me the shivers too!
If you haven’t read the first two books, In the Blink of An Eye and Leave No Trace, then STOP reading this review now and go buy the first two books IMMEDIATELY.
This is fast becoming one of my favourite series. If you are still reading this review despite my comments above, I will try to summarise for you.
In The Blink of An Eye (book 1) introduces the reader to DCS Kat Frank. She recently lost her husband and is now a widowed single mother. After his tragic passing, she returned to work as a detective. She is picked to lead a new pilot programme where she is teamed up with an Artificially Intelligent Detective called Lock. It’s basically AI versus human experience and logic versus instinct as Kat and Lock investigate cold cases.
I would strongly recommend that you read the series in order. There are several members of the team you need to get to know. Books 1 and 2 introduce you to everyone in detail, including their back stories.
The latest book, Human Remains starts when a headless, handless body is found buried on a local farm. Kat, Lock and the rest of the team are tasked with finding out who the victim is. There is also a parallel story running as someone is watching Kat and wants revenge at whatever cost.
Kat is also battling her emotions as her only son is now away at University. She is struggling with an empty nest and loneliness. It doesn’t help that one of her team is now on maternity leave and she is feeling threatened because one of her past cases is hitting the headlines for all the wrong reasons.
The lines between AI and friend are beginning to blur. Kat and Lock start to depend upon each other more and more throughout this story.
I’m not going to say much more.. but THAT ending gave me the shivers too!
May 25, 2025
⭐️✨Still going strong
Third in the series and still an amazing read! Just the right amount of thrill, mystery, tension, and a suspicious ending that has me really hoping for a fourth book!!!!! Fingers and toes crossed :)
Also, Rose Akroyd’s narration 🙌🏾 remains very well done throughout the series.
Third in the series and still an amazing read! Just the right amount of thrill, mystery, tension, and a suspicious ending that has me really hoping for a fourth book!!!!! Fingers and toes crossed :)
Also, Rose Akroyd’s narration 🙌🏾 remains very well done throughout the series.
September 27, 2026
HUMAN REMAINS is #3 in the Kat and Lock series. Most of my GoodReads friends have already reviewed it, so I won't write a long dissertation, just note what I felt while reading it. (Although I do wish the publishers would make the Libby copy available earlier in North America; it seems like I've been waiting forever for my Canadian library to acquire it.)
The plot of Human Remains is easy to follow if you have read the earlier two instalments of this series, as I have. DCS Kat Frank is assigned a cold case after a decayed, dismembered body is discovered within the confines of a produce farm. Initially, she needs to identify it, a difficult task given the level of decay and dismemberment. Then she has to find the killer. Running concurrent with this murder case is an intermittent series of brief reflections by someone who is trying to harm Kat; this obsession appears to be connected to a case she investigated and closed several years earlier—well before she became involved with Lock, the Artificial Intelligence Detecting Entity.
Most readers are going to solve these cases sooner than Kat does. I correctly identified the killer in the "decayed body" case by the 40% point of the book (and Kat did at roughly the 70% point). I correctly identified the person harassing Kat, and their motivation for this harassment by the 30% point in the book (and that person confronted Kat at roughly the 80% point). So readers looking for a "mystery" are going to be disappointed. The charm of this novel is the humour provided by Lock (just not quite human), the very human emotions expressed by Kat and her assistant DI Rayan Hassan, and the short "information descriptions" about a variety of technical topics. (Admittedly, some readers might find these short expository passages boring if they don't want to be illuminated about technology, but I thought they were well written and brief enough that they didn't bore me.)
It was an enjoyable read, and as I neared the end, I internally rated it a high 4 stars. Then came the ending, and everything I believed before, everything I expected, was turned around. Suddenly Lock was not humorous; the AIDE was dangerous—but not because of an "evil" intention on anyone's part (nor on Lock's part). Wham! I saw AI through the eyes of those working with AI. Not evil, but because not human, it cannot make judgements based on human morality.
That ending turned a good 4-star book into a strong 5-star one.
This time I am in complete harmony with my GoodReads friends, four of whom have also rated it a 5-star read, and one who rated it a 4.5-star read. None have rated it below 4.5 stars.
Thanks to the Greater Victoria Public Library for providing the ebook that I read.
~~~~~~~~~~~~~~~~~~~~
My reviews for other books in the series:
Leave No Trace (Kat and Lock, #2)
In the Blink of an Eye (Kat and Lock, #1)
~~~~~~~~~~~~~~~~~~~~
The plot of Human Remains is easy to follow if you have read the earlier two instalments of this series, as I have. DCS Kat Frank is assigned a cold case after a decayed, dismembered body is discovered within the confines of a produce farm. Initially, she needs to identify it, a difficult task given the level of decay and dismemberment. Then she has to find the killer. Running concurrent with this murder case is an intermittent series of brief reflections by someone who is trying to harm Kat; this obsession appears to be connected to a case she investigated and closed several years earlier—well before she became involved with Lock, the Artificial Intelligence Detecting Entity.
Most readers are going to solve these cases sooner than Kat does. I correctly identified the killer in the "decayed body" case by the 40% point of the book (and Kat did at roughly the 70% point). I correctly identified the person harassing Kat, and their motivation for this harassment by the 30% point in the book (and that person confronted Kat at roughly the 80% point). So readers looking for a "mystery" are going to be disappointed. The charm of this novel is the humour provided by Lock (just not quite human), the very human emotions expressed by Kat and her assistant DI Rayan Hassan, and the short "information descriptions" about a variety of technical topics. (Admittedly, some readers might find these short expository passages boring if they don't want to be illuminated about technology, but I thought they were well written and brief enough that they didn't bore me.)
It was an enjoyable read, and as I neared the end, I internally rated it a high 4 stars. Then came the ending, and everything I believed before, everything I expected, was turned around. Suddenly Lock was not humorous; the AIDE was dangerous—but not because of an "evil" intention on anyone's part (nor on Lock's part). Wham! I saw AI through the eyes of those working with AI. Not evil, but because not human, it cannot make judgements based on human morality.
That ending turned a good 4-star book into a strong 5-star one.
This time I am in complete harmony with my GoodReads friends, four of whom have also rated it a 5-star read, and one who rated it a 4.5-star read. None have rated it below 4.5 stars.
Thanks to the Greater Victoria Public Library for providing the ebook that I read.
~~~~~~~~~~~~~~~~~~~~
My reviews for other books in the series:
Leave No Trace (Kat and Lock, #2)
In the Blink of an Eye (Kat and Lock, #1)
~~~~~~~~~~~~~~~~~~~~
September 20, 2025
Absolutely OUTSTANDING! 👏🏻
August 24, 2025
~3.5~
I ate this one up, then toward the end, the story took a turn I wasn't expecting, and I feel some kind of way about it.
Something happens to one of the main characters, something they definitely didn't deserve. I don't know why the author went there, but I don't like it.
Kat is on my last nerve. Her defensiveness and stubbornness were at an all time high, and I lost a lot of respect for her. How could someone training to be a cop not report something like that?
Lock is acting ten shades of sus. He wants a body. How far will he go to get one?
Where is book 4 when you need it?
I ate this one up, then toward the end, the story took a turn I wasn't expecting, and I feel some kind of way about it.
Something happens to one of the main characters, something they definitely didn't deserve. I don't know why the author went there, but I don't like it.
Kat is on my last nerve. Her defensiveness and stubbornness were at an all time high, and I lost a lot of respect for her. How could someone training to be a cop not report something like that?
Lock is acting ten shades of sus. He wants a body. How far will he go to get one?
Where is book 4 when you need it?
January 22, 2026
Book 4 immediately please.
Everything you hope for in a mystery thriller, mixed with a whole lot of heart, community and warmth.
Audiobook also available on Book Beat - sign up here for 3 months free!
Everything you hope for in a mystery thriller, mixed with a whole lot of heart, community and warmth.
Audiobook also available on Book Beat - sign up here for 3 months free!
August 8, 2026
Definitely addicted to this series now
I need to keep reading!
I need to keep reading!
April 23, 2025
DCS DCS Kat Frank has a new case to solve.
Oh dear. I absolutely adored the first two books, In the Blink of An Eye and Leave No Trace, in the DCS Kat Frank and AIDE Lock series, so how I’m supposed to review the third, Human Remains, without repeating myself I have no idea, except to say that I think this third book is even better than the first two. I would also say that there is no need to have read the earlier books thoroughly to enjoy Human Remains, but not to do so is to miss out on a fantastic series.
I loved every aspect of this exciting, skilful and gripping thriller. I’m not normally a huge fan of police procedural narratives, but Human Remains transcends the usual genre into the most magnificent read by weaving in scientific and technological elements completely naturally, and totally convincingly. Terminology is included so that the reader feels educated. However, the terminology never impedes the flow of the narrative. As a result, it’s hard to over-emphasise just how brilliant, how intelligent and how compelling the story is.
To some extent the investigation into the headless body found at the beginning of the story is only a fraction of the interest. The developing relationships within Kat’s team and family, the way Lock continues to evolve, Kat’s own past, and the scientific development of AI are layered, mesmerising and gripping aspects. What Jo Callaghan does so hypnotically is to take technology and science and overlay these aspects with humanity and emotion in a way that leaves the reader reeling. It’s impossible to explain why and how this happens without revealing too much of the plot for others, but rest assured this is a plot with heart-thumping moments and deep emotion. It’s truly fabulous.
And the title is just wonderful. Human Remains fits every aspect of the narrative, from the literal human remains found in the first few pages of the story, to the aspects of us that are left when reason, logic and rationality are stripped away. As a result, Human Remains entertains completely, but at the same time suggests the potential future for AI – and all humanity – so that just as the reader believes they have formed an immutable opinion, Jo Callaghan rips away certainty and leaves her readers confounded, unsettled and desperate for more.
The themes in the story illustrate the power of social media, the potential and threat of AI, grief and loyalty, with practical policing as well as other aspects exploring emotional and human connection so that Human Remains is multi-layered and sensitively resonant.
In case it isn’t clear (and I am aware of some vagueness here for fear of spoilers), I thought Human Remains was fantastic. I cannot recommend it highly enough and I am genuinely desperate for more from Kat and Lock. Brilliant, brilliant stuff. Jo Callaghan is a must read author!
Oh dear. I absolutely adored the first two books, In the Blink of An Eye and Leave No Trace, in the DCS Kat Frank and AIDE Lock series, so how I’m supposed to review the third, Human Remains, without repeating myself I have no idea, except to say that I think this third book is even better than the first two. I would also say that there is no need to have read the earlier books thoroughly to enjoy Human Remains, but not to do so is to miss out on a fantastic series.
I loved every aspect of this exciting, skilful and gripping thriller. I’m not normally a huge fan of police procedural narratives, but Human Remains transcends the usual genre into the most magnificent read by weaving in scientific and technological elements completely naturally, and totally convincingly. Terminology is included so that the reader feels educated. However, the terminology never impedes the flow of the narrative. As a result, it’s hard to over-emphasise just how brilliant, how intelligent and how compelling the story is.
To some extent the investigation into the headless body found at the beginning of the story is only a fraction of the interest. The developing relationships within Kat’s team and family, the way Lock continues to evolve, Kat’s own past, and the scientific development of AI are layered, mesmerising and gripping aspects. What Jo Callaghan does so hypnotically is to take technology and science and overlay these aspects with humanity and emotion in a way that leaves the reader reeling. It’s impossible to explain why and how this happens without revealing too much of the plot for others, but rest assured this is a plot with heart-thumping moments and deep emotion. It’s truly fabulous.
And the title is just wonderful. Human Remains fits every aspect of the narrative, from the literal human remains found in the first few pages of the story, to the aspects of us that are left when reason, logic and rationality are stripped away. As a result, Human Remains entertains completely, but at the same time suggests the potential future for AI – and all humanity – so that just as the reader believes they have formed an immutable opinion, Jo Callaghan rips away certainty and leaves her readers confounded, unsettled and desperate for more.
The themes in the story illustrate the power of social media, the potential and threat of AI, grief and loyalty, with practical policing as well as other aspects exploring emotional and human connection so that Human Remains is multi-layered and sensitively resonant.
In case it isn’t clear (and I am aware of some vagueness here for fear of spoilers), I thought Human Remains was fantastic. I cannot recommend it highly enough and I am genuinely desperate for more from Kat and Lock. Brilliant, brilliant stuff. Jo Callaghan is a must read author!
June 26, 2026
4.75/5
This is book three in the Kat and Locke series where they investigate a body which has been found on a farm.
I have been loving this series and this is definitely my favourite book so far! The case was great but what made this book so special was the ending! All the emotions 😭
This is book three in the Kat and Locke series where they investigate a body which has been found on a farm.
I have been loving this series and this is definitely my favourite book so far! The case was great but what made this book so special was the ending! All the emotions 😭
September 18, 2025
⭐️⭐️⭐️⭐️⭐️
Human Remains by Jo Callaghan is a gripping, intelligent, and thought-provoking thriller. The writing is sharp and immersive, blending strong character development with a fresh and original premise. It balances suspense with real emotional depth, keeping you hooked from start to finish. A must-read for anyone who loves crime fiction with a unique twist.
Human Remains by Jo Callaghan is a gripping, intelligent, and thought-provoking thriller. The writing is sharp and immersive, blending strong character development with a fresh and original premise. It balances suspense with real emotional depth, keeping you hooked from start to finish. A must-read for anyone who loves crime fiction with a unique twist.
June 13, 2025
Oh my goodness, review to follow. A superb addition to the series. I can't wait for book #4 despite feeling trepidation as to what it might contain!
May 11, 2025
This was another excellent instalment to the Kat and Lock series, there is something so special and unique about these books I would love to see them made into a tv series someday.
This book starts with a dismembered body being found. The hands and head are missing making it very difficult to get the body identified and the locals are being less than helpful.
This is made more stressful for Kat when one of her old cases makes its way into the public again, and not in a good way. Kat is also struggling with loneliness and grief and her relationship with Lock seems to change more in this book becoming dare I say more like a friendship!
I’m really hoping a book 4 is on the way it still feels so new and fresh.
This book starts with a dismembered body being found. The hands and head are missing making it very difficult to get the body identified and the locals are being less than helpful.
This is made more stressful for Kat when one of her old cases makes its way into the public again, and not in a good way. Kat is also struggling with loneliness and grief and her relationship with Lock seems to change more in this book becoming dare I say more like a friendship!
I’m really hoping a book 4 is on the way it still feels so new and fresh.
April 29, 2025
Excellent series. Great story.
January 4, 2026
I love this series and its real time interrogation of the positive and negative implications of AI with an AI Detective sidekick (AIDE Lock)
DCS Kat Frank's "relationship" with her "partner" peaks and troughs. He can analyse reams of data in seconds (but without the ability to vary the exact instruction given) whilst at the same time these uses of AIDE Lock nudge into the heart of the team hierarchy, displacing her human DI who is able to absorb facts, unknowns, possible connections and instinct. The need for "out of the box" thinking in complex cases is, currently, a failure of this AI.
There seems to be a growing trend of having lead detectives pursued by threats on their professional judgement and personal choices. I am particularly thinking of DCI Matilda Darke in Michael Wood's brilliant series. In Human Remains, the reader knows from the start that Kat's life is under threat and this thread begins to needle into the case of the headless, handless corpse found on farmland. I understand these sub-plots widen the story but am not a great fan.
That said, really enjoyed and excited (troubled?) to see what happens next!
DCS Kat Frank's "relationship" with her "partner" peaks and troughs. He can analyse reams of data in seconds (but without the ability to vary the exact instruction given) whilst at the same time these uses of AIDE Lock nudge into the heart of the team hierarchy, displacing her human DI who is able to absorb facts, unknowns, possible connections and instinct. The need for "out of the box" thinking in complex cases is, currently, a failure of this AI.
There seems to be a growing trend of having lead detectives pursued by threats on their professional judgement and personal choices. I am particularly thinking of DCI Matilda Darke in Michael Wood's brilliant series. In Human Remains, the reader knows from the start that Kat's life is under threat and this thread begins to needle into the case of the headless, handless corpse found on farmland. I understand these sub-plots widen the story but am not a great fan.
That said, really enjoyed and excited (troubled?) to see what happens next!
June 10, 2026
З кожною книгою мені ця серія подобається все більше і більше
August 31, 2025
Her best yet. You need to read these in chronological order. I was sceptical about reading In the Blink of an Eye her first novel about using an AI hologram to assist detectives. However it was fascinating and this latest one just keeps challenging the reader's thoughts on trusting AI. Really looking forward to her 4th book.
May 1, 2025
Actual rating 4.5.
February 10, 2026
We’re back with DCS Kat Frank, AIDE Lock and the Future Policing Unit as they face the prospect of the return of a serial killer. The only problem is, Kat caught him years ago….didn’t she? Accused of putting the wrong man behind bars all those years ago, AIDE Lock pursues the truth with relentless logic. Add in a shadowy figure looking for revenge and plenty of twists and turns, and you have another amazing instalment of the series!
November 8, 2025
Ibland är det lite märkligt vilka böcker man (jag) prioriterar att läsa. Merparten av böckerna jag får/köper får vänta i många, många år på att bli lästa. Och så finns det sådana som Rester av döden, som jag läser bara två veckor efter att den kom hem till mig. Olika falla ödets lotter.
Att Jo Callaghan jobbar/har jobbat med AI-forskning är väldigt tydligt i de här böckerna. Dessa tre, som jag hittills har läst, har varit det enda jag råkat på som poängterar både för- och nackdelar med AI. Jag gillar verkligen det. Dessutom lyckas hon göra det utan att föreläsa eller använda pekpinnar. Personligen så tycker jag att det är uppenbart att det finns en del uppgifter som AI inte kommer att kunna utföra (under överskådlig framtid). Det stora problemet är att den tar bara hänsyn till fakta och statistik (och har ingen aning om huruvida inmatade uppgifter är sanna eller falska). Men människor är inte fakta och statistik. Människor är känslor och irrationellt beteende.
Rester av döden är minst lika bra som de två tidigare böckerna, men jag är lite rädd för att böckerna tycks vara på väg åt ett håll som jag nog inte tycker om. I vilket fall så förbereder jag mig på en lång väntan på nästa bok. Den verkar vara planerad att släppas, på engelska, i maj nästa år.
OBS! Detta är en kraftigt förkortad text. Hela finns på min blogg
Att Jo Callaghan jobbar/har jobbat med AI-forskning är väldigt tydligt i de här böckerna. Dessa tre, som jag hittills har läst, har varit det enda jag råkat på som poängterar både för- och nackdelar med AI. Jag gillar verkligen det. Dessutom lyckas hon göra det utan att föreläsa eller använda pekpinnar. Personligen så tycker jag att det är uppenbart att det finns en del uppgifter som AI inte kommer att kunna utföra (under överskådlig framtid). Det stora problemet är att den tar bara hänsyn till fakta och statistik (och har ingen aning om huruvida inmatade uppgifter är sanna eller falska). Men människor är inte fakta och statistik. Människor är känslor och irrationellt beteende.
Rester av döden är minst lika bra som de två tidigare böckerna, men jag är lite rädd för att böckerna tycks vara på väg åt ett håll som jag nog inte tycker om. I vilket fall så förbereder jag mig på en lång väntan på nästa bok. Den verkar vara planerad att släppas, på engelska, i maj nästa år.
OBS! Detta är en kraftigt förkortad text. Hela finns på min blogg
April 12, 2025
Brilliant read - having read the first two books in the Kat and Lock series, I couldn’t wait to read this. I dropped my current reads and went straight in and devoured the book in the space of 24 hours. It was absolutely fantastic!
The crime genre is one I thoroughly enjoy and I will 100% agree with the cover that it’s the must read crime novel of the year. I became immediately engrossed and I was super happy to be back with Kat and Lock; they work very well together.
It’s a great storyline with the investigation into the body that was found on a farm and also the story running side by side to the investigation; Kat is being watched and this person wants revenge. We also get a podcast throughout which refers to a previous investigation that Kat worked on and the conviction of the Aston Strangler.
Kat is such an incredible and strong character who not only has the stress and pressure of her ranking in the force; she’s grieving and suffering loneliness especially with her son being away. I feel like Lock played a big part in Human Remains and often reminded Kat that he noticed when actually, things were getting a bit too much but she would completely shut him down and say she was fine.
The ending was just wow, so much happened in the last quarter of the book and done so brilliantly. I absolutely cannot wait to see where this goes but then I’m nervous about it, especially with Kat’s thoughts!
Brilliant read and I would recommend that if you’ve never the series, to start with book 1 - In The Blink of an Eye, it’s definitely worth getting to know the characters and their back stories and following the books in order.
The crime genre is one I thoroughly enjoy and I will 100% agree with the cover that it’s the must read crime novel of the year. I became immediately engrossed and I was super happy to be back with Kat and Lock; they work very well together.
It’s a great storyline with the investigation into the body that was found on a farm and also the story running side by side to the investigation; Kat is being watched and this person wants revenge. We also get a podcast throughout which refers to a previous investigation that Kat worked on and the conviction of the Aston Strangler.
Kat is such an incredible and strong character who not only has the stress and pressure of her ranking in the force; she’s grieving and suffering loneliness especially with her son being away. I feel like Lock played a big part in Human Remains and often reminded Kat that he noticed when actually, things were getting a bit too much but she would completely shut him down and say she was fine.
The ending was just wow, so much happened in the last quarter of the book and done so brilliantly. I absolutely cannot wait to see where this goes but then I’m nervous about it, especially with Kat’s thoughts!
Brilliant read and I would recommend that if you’ve never the series, to start with book 1 - In The Blink of an Eye, it’s definitely worth getting to know the characters and their back stories and following the books in order.
May 10, 2025
The DCS Kat Frank and AIDE Lock series has fast become one of my favourite crime/police series and so I was very eagerly looking forward to reading book three, Human Remains. As expected I loved it.
The main story at first appears to be the discovery of a headless and handless body on a farm and the team's investigation into what happened and who the body belongs to. However, it's not long before Kat's biggest case comes back to haunt her, that of the Aston Strangler. Kat solved the case back then but now a podcast is casting doubt as to whether the right person was caught and imprisoned.
The team are back together and one of the strongest thing about this series is the characterisations and the way that individual members of the team interact with Lock, not to mention the sheer brilliance of Lock itself. The AI detective is brilliantly written and portrayed and I love how it can read hundreds of articles in seconds, or watch numerous TV series in the same amount of time. There's no denying it is a huge help within the team in terms of doing the work that it would take a human days or weeks to get through, but some developments in this book really highlighted the potential for AI to be misused or relied on too heavily.
I was absolutely gripped by this book, particularly the last third or so where the pace accelerated rather quickly. I'm desperate now for book four, especially because of how this one ended. Talk about chilling! Human Remains is an absolutely fantastic and thoroughly absorbing read and I very highly recommend it and the whole series so far.
The main story at first appears to be the discovery of a headless and handless body on a farm and the team's investigation into what happened and who the body belongs to. However, it's not long before Kat's biggest case comes back to haunt her, that of the Aston Strangler. Kat solved the case back then but now a podcast is casting doubt as to whether the right person was caught and imprisoned.
The team are back together and one of the strongest thing about this series is the characterisations and the way that individual members of the team interact with Lock, not to mention the sheer brilliance of Lock itself. The AI detective is brilliantly written and portrayed and I love how it can read hundreds of articles in seconds, or watch numerous TV series in the same amount of time. There's no denying it is a huge help within the team in terms of doing the work that it would take a human days or weeks to get through, but some developments in this book really highlighted the potential for AI to be misused or relied on too heavily.
I was absolutely gripped by this book, particularly the last third or so where the pace accelerated rather quickly. I'm desperate now for book four, especially because of how this one ended. Talk about chilling! Human Remains is an absolutely fantastic and thoroughly absorbing read and I very highly recommend it and the whole series so far.
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