THE MERMAIDS SINGING, by Val McDermid

Book #1 in the Tony Hill/Carol Jordan series. A chilling, in places horrific, look into the mind and methods of a sadistic serial killer and the police who work round the clock to try to stop further grisly killings. Set in Bradford, an English city, this many-faceted police procedural focuses on not only the crime but the politics and personalities of the coppers, both traditional and forward-thinking. This is a series that promises to be rough and very tough, not for the squeamish or tender-hearted.
Dr. Tony Hill, police profiler with a deeply-guarded personal secret, is grudgingly accepted as advisor by some on the force. His liasson, attractive Detective Inspector Carol Jordan, welcomes any help, no matter how theoretical. She walks a fine line as she finds the consultant appealing. The author skillfully manages to not give away the underlying traumas that makes the relationship so prickly and, for Hill, impossible. He admires her razor-sharp intellect, but can't afford to admire anything more.
As the body count mounts and Hill develops his profile of the ingenious killer, he fails to  understand that two can play cat and mouse. Jordan, obsessed with preventing further atrocities, knows the killer could target Hill, but somehow fails to convince him to be more wary. But almost any level of vigilance would be useless against this inventive, skilled murderer.
Too late Hill puts the puzzle together, and must face the full horror of the murderer's mind and method with only minutes to deflect the killer. Too late Jordan figures it all out. The final race against time is stay-up-all-night tense and compelling.
A pull-no-punches read for those devoted to the darker end of police procedurals. It's a four.