Reuben Maitland is still operating in a rogue laboratory using some of his old staff and contacts to earn a living. Working outside the law, sometimes for notorious crooks, and not using his expertise for apprehending criminals is frustrating and not fulfilling. In addition, builders are approaching closer to his hidden lab with their demolishing equipment.

Unsurprisingly, therefore, he is very ready to work with his old colleagues to find out who is misusing his DNA work. Someone is using DNA profiling from GeneCrime, and the forensic unit's database files to forecast people who are genetically prone to violence. These candidates are being systematically targeted with threats and intimidation designed to make them snap. Everyone has their breaking point, but someone is finding those with more violent tendencies and pushing them to act.

Meanwhile, a random killer is murdering commuters on the tube, leaving no apparent trace. Sarah Hirst and the forensic unit are trying to solve the series of crimes terrorising London passengers, without being able to find any clues or motive. Instability in the unit and the challenges of new responsibilities make the job harder for everyone involved.

Gradually, Reuben's investigation into those abusing his work starts to draw him back into the work of GeneCrime, partly from necessity and partly by his attraction to Sarah. As he tracks down who is creating killers, he himself is put in harm's way both from the tube killer and from an old adversary.

This is the third in the GeneCrime series and, as with the others in the series, Reuben is still a conflicted workaholic and his colleagues spend a lot of their time questioning whether they can trust him, or even each other. It is rare that this type of crime thriller is based in a UK city; the style of writing, forensic detail, and some of the shocking violence is more usual in a US backdrop. Tense and violent, this is not a light book, but it makes gripping reading.

Whilst some of the writing is graphic, the scientific concepts and theories are interesting and thought provoking and there are also the ethical issues around DNA typing and data storage. These, along with the interwoven plot and exploration of the different characters involved, made the book far more interesting than a simplistic CSI story and I look forward to book four and seeing how Reuben's career progresses.

Amanda Brown, England
March 2009