Leave No Trace (Kat And Lock Book Two) by Jo Callaghan

 

Leave No Trace (Kat and Lock Book Two) by Jo Callaghan.

Published 28th March 2024 by Simon and Schuster.

From the cover of the book:

One detective driven by instinct, the other by logic.
It will take both to find a killer who knows the true meaning of fear . . .

When the body of a man is found crucified at the top of Mount Judd, AIDE Lock – the world’s first AI Detective – and DCS Kat Frank are thrust into the spotlight as they are given their first live case.

But with the discovery of another man’s body – also crucified – it appears that their killer is only just getting started. With the police warning local men to be vigilant, the Future Policing Unit is thrust into a hostile media frenzy as they desperately search for connections between the victims. But time is running out for them to join the dots and prevent another death.

For if Kat and Lock know anything, it’s that killers rarely stop – until they are made to.

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The Future Policing Unit (FPU) has performed well in its pilot phase, seeking answers to some tricky cold cases, and DCS Kat Frank is keen to set her team to work on a live case. When the body of a naked man is found crucified on a hill, familiarly known as Nuneaton's Nipple, Kat finally gets her wish, and the FPU get their chance to show exactly what they can do with the help of AIDE Lock, the world's first AI detective.

However, when a second victim turns up, bearing all the hallmarks of the work of a serial killer on a mission, the unfortunate media frenzy that ensues puts the ground-breaking FPU under the spotlight in undesirable ways - and puts enormous pressure on the team to ease public fears as soon as possible...

Having cut their teeth on several cold cases, the FPU now get the opportunity to work on a live investigation which tests them to the very limit in terms of their personal and professional lives. Returning to the criminal coal-face, DCS Kat Frank heads up a team comprising ambitious DI Hassan, a now very pregnant DS Browne, super-smart Professor Okonedo, and Okonedo's incredible invention AIDE (Artificially Intelligent Detective Entity) Lock - an AI capable of Deep Learning. The team are bolstered this time around by two intriguing new members too, Karen-from-comms (affectionately referred to as KFC), and an unconventional pathologist in Dr Judith Edwards, both of whom I can see being firm fixtures in the books that follow.

The FPU's first live case is far from easy to solve, and the work of the team is hampered enormously by the pressure from above to move fast to ease the fears the public, which have been stoked by sensational media headlines about the profile of the (white male) victims, rumours of a serial killer, and misgivings about the involvement of Lock in solving the case. The pace is fast and furious, threaded with delicious detail about the police procedural elements (some of which are fascinatingly cutting-edge), set against a snowy backdrop that adds lovely atmosphere. The clever combination of narrative (from the FPU team, and the killer), transcripts of police interviews, and social media comments, come together to move the story along beautifully - all the way to the glorious wintry, climax where complicated judgement calls have to be made.

Callaghan does an incredible job of building on the tentative relationships between the members of the FPU, that began in the first book, to whack up the emotional content. As the point of view flips between Kat and her team, there are intensely touching moments that show how they have bonded, and are supporting each through their personal trials and tribulations. The relationship between Kat and Lock, with their continuing verbal sparring sessions about the pros and cons of logic vs intuition, remains the spine of the novel and provides so many moments of humour and heartache, as Kat gets to grips with the loss of her husband and empty-nest syndrome, and Lock learns about what it means to be human. Lock's character in particular gains real depth as he unexpectedly struggles with existential dread, and is forced to confront different, and ever more incomprehensible, aspects of human nature - I love that he becomes more playful in this second book too.

If Callaghan's writing was not impressive enough in terms of plot, character development, and emotive content, she manages to also thread a bevy of thought-provoking themes into this book. Her background as a researcher in AI in the workplace gives her the ability to present ways in which AI can be of benefit in solving crime, while highlighting the times when a human element gives the edge over facts, statistics, and data analysis, and I really enjoy the engaging way she explores this through Kat and Lock's partnership. This particular case throws up many other uncomfortable themes to examine as well, especially when it comes to violent crime; mental health; the role of the media; and the pursuit of justice. She also has some very interesting, and anger inducing, things to say about how race and gender can be used as weapons to discriminate, and pervert the truth.

In the Blink of an Eye was a winner of a debut, and this second book confirms that Jo Callaghan is so much more than a flash in the pan. I absolutely consumed Leave No Trace from cover to cover, and loved it even more that the first book, which is saying a lot. There is a spine-chilling little parting shot to lead you into book three, and I am already chomping at the bit for more...

Leave No Trace is available to buy now in hardcover, ebook and audio formats.

Thank you to Simon and Schuster for sending me a proof of this book in return for an honest review, and to Random Things Tours for inviting me to be part of this blog tour.

About the author:

Jo Callaghan works full time as a senior strategist, carrying out research into the future impact of AI and genomics on the workforce. She was a student of the Writers' Academy Course (Penguin Random House) and was longlisted for the Mslexia Novel Writing Competition and Bath Novel Competition.

After losing her husband to cancer in 2019 when she was just forty-nine, she started writing In the Blink of an Eye, her debut crime novel, which explores learning to live with loss and what it means to be human. 

She lives with her two children in the Midlands, where she spends far too much time tweeting as @JoCallaghanKat and is currently working on further novels in the series.