Mo Hayder - Gone

Book review by showhost March 2013
Yipee I.'ve found a new crime writer I like.  A gritty, suspense, crime writer.
DI Jack Caffrey, of Bristol major crime investigation unit is interviewing the distraught victim of a car jacking.  The car was taken by force, the jacker was wearing a Santa clause mask,  but on the back seat was an 11 year old girl. The girl is still missing. When  the jacker communicates with the police they realise that this is only the start and other car-jackings are about to follow. Working with DI Jack is Flea Marley and her Underwater Search Unit (USU). These two characters seem to have some sort of history together which I assume was constructed in a previous novel.
The car jacker is out manoeuvring the police and sending false leads and finding the safe houses where the families are moved to.  Will they find the girls in time? 
I'm not normally great at working out who the perpetrator is but in this instance I did, so it must have been fairly obvious.  I also agree with another reviewer that it kind of lost its momentum slightly towards the predictable end. Nor did I work out why the perp kept looking at another 'case' - what did it have to do with this particular story?  I kept thinking it was going to lead somewhere, to something, to do with the car jacker ......
I found the book pacy and addictive but wondered if the author should have finished it sooner.