The Mermaids Singing by Val McDermid

England is faced with a serial killer.  He targets gay men and tortures them with medieval tactics and painstakingly recreated devices before killing them.  Baffled, the police bring in a new resource.  Dr. Tony Hill has been the head of the criminally insane hospital unit that houses England's existing serial killers for several years.  As such, he has more insight into the minds and motivations of such men than the average policeman.

Detective Inspector Carol Jordan is intent on making her way to the top.  She realises that as a woman detective, she will have to work twice as hard, and she is fine with that.  Carol is selected to work with Dr. Hill, and she finds his methods fascinating.  His work, especially the psychological profile he prepares, shows her different ways of bringing investigations to a successful close. 

But the killings go on.  More men are killed and shockingly, one is a member of the police force.  The killer is obviously thumbing his nose at the police, defying them to discover his identity and end his murderous spree.  Will Dr. Hill and Dectective Jordan, along with the task force dedicated to the case manage to end his reign of terror?

The Mermaids Singing is Val McDermid's introductory volume in the Hill/Jordan series.  She has since written six others. The books are very popular and have also been dramatized into a miniseries.  McDermid's forte is strong characterization and the relationships formed between members of a police force and between the law-breakers and the law-enforcers.  This book is enthusiastically recommended for all mystery or thriller fans.