No Age to Die — John Dean

When an old lag is released from a prison sentence for child-murder, Detective Chief Inspector John Blizzard is ordered to warn him about his future conduct. But, as news of the release spreads and another teenager is killed within hours, feelings run high in the local community and Blizzard and his sergeant, David Colley, find themselves struggling to contain an ugly and rapidly escalating situation.
As the investigation develops, their attention turns to the local church run by a terrified clergyman and a group of sinister evangelicals who insist that even the worst sinner can be saved by the light of the Lord.
The detectives soon discover that behind the holy facade beats a heart of evil and a dark secret, which are worlds away from love and forgiveness.