Gone by Mo Hayder

Someone is taking young girls.  He runs up as their mothers are about to drive off in a Santa mask and takes the girl along with the car.  So far, four girls have been taken with no real progress being made on the case.  He released two for reasons of his own, but the others are missing, their parents in agony.

Detective Jack Caffery heads up the case.  This one is personal to him, as his own brother disappeared thirty years ago and was never found.  It drove Caffery into police work and makes him the haunted, driven man that he is.  That makes him a successful detective while it takes its toll on his body and spirit.

One of those searching for the girls is Flea Marley, a police diver who heads up the search and rescue team.  She has a feeling about an abandoned canal, part of which is a tunnel, that is near where one of the parents' cars is found.  The police mount an intensive search but nothing is found and Flea is chastised for wasting resources on a hunch.  Her next hunch takes her on a solo search as she doesn't want to be wrong again and soon she is also in trouble.

The case progresses slowly and it seems the kidnapper is always one step ahead of the police.  Jack even consults a strange figure, The Walking Man, who has walked the countryside for years and seems to always know something or have a way of framing problems that stirs Jack's instincts.  The Walking Man also lost a daughter many years ago and searches constantly for clues about her fate.

This is the fifth in the Jack Caffery mystery series.  Readers will be entranced by Hayder's involved plotting and the views into the detectives' motives and problems.  The plot twists are exciting and come as a surprise to the reader.  This is one of the best detective series to be found.  This book is recommended for mystery readers.