How the Dead Speak by Val McDermid (Tony Hill & Carol Jordan #11)

'We are all creatures of habit. Even murderers . . .'
When human remains are discovered in the grounds of an old convent, it quickly becomes clear that someone has been using the site as their personal burial ground. But with the convent abandoned long ago and bodies dating back many years, could this be the work of more than one obsessive killer?
The investigation throws up more questions as the evidence mounts but, after their last disastrous case, Tony Hill and Carol Jordan can only watch from afar. As they deal with the consequences, someone with a terrifying routine is biding their time - and both Tony and Carol find themselves closer to the edge than they have ever been before . . .
Masterful and filled with suspense, this an electrifying, heart-racing thriller from the number one bestseller.