Leave No Trace by Jo Callaghan

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...

The police issue a controversial warning to local men to be vigilant: do not walk home alone at night, do not leave a pub with a stranger… 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, so they must combine their human instinct and algorithms to catch the killer before the strike again.

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

About the author

Jo Callaghan works fulltime as a senior strategist, where she has carried out research into the future impact of AI and genomics on the workforce. 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. In The Blink of an Eye was selected for BBC 2’s ‘Between the Covers’ in Spring 2023, and Jo was a featured debut at Harrogate Crime Festival and Bloody Scotland Festival. She lives with her two children in the Midlands. Leave No Trace is her second novel.

Review

So somehow I managed to miss all the amazing reviews and hype for the first book in the series ‘In The Blink Of An Eye’ so I picked it up to read before this one! Oh my, it was amazing and I was so thankful I could dive straight into ‘Leave No Trace’ and continue exploring the wonderful relationship between Kat and Lock. This outing could be read as a standalone read but I do recommend always getting in at the start of a series and plus the first book is a blistering cracker of a read! This book just builds on the foundations of that and I just adored this one.

DCS Kat Frank’s partner Aide Lock is the world’s first AI detective and after solving a series of cold cases they have been given their first ‘live’ case. A man has been found at the top of a landfill crucified and it's up to Kat and Lock to prove their worth but they are soon engulfed in a media storm when Lock’s involvement is announced. But when a second body is found crucified they know they have to find the killer before they strike again.

The use of AI in crime books is becoming more common but very few have such a unique character as they do in Aide Lock. Due to his perpetual learning capability, he is steadily becoming more empathetic and ‘human’ in his interactions with Kat and the team. But he is still a machine and Kat is battling an inner debate about Lock being purely mechanics or something more. Kat is beginning to rely on him more in a personal sense as she is still grieving from the loss of her husband and now her son Cam has left home to go to university in Bristol. She is certainly feeling that ‘empty best syndrome’ and throwing herself into work to try and combat that. I really love Kat and her story, she is such a strong lady, highly intelligent and very loyal.

‘Leave No Trace’ deals with some strong topics - misogyny, sexual violence, revenge and desperation. Although, they can be dark topics they have been dealt with with great empathy and show the author to be a nuanced writer. I particularly loved Rayan’s protectiveness of the Professor. Plus, the author has turned the story on it’s head by making men the victims for once and this narrative really places a mirror on modern society.

I devoured this book in one sitting it was that engrossing! It captivated my attention and I flew through those pages. I love the growing bonds in the team and despite Lock being the standard of logic and reason it's his stumbles and wry remarks that provide the light relief in this book. It's full of poignant and thought-provoking moments and I can't wait to see more from these characters! Bring on the next book.

Let me know if you pick this one up!