Broken Promise (Promise Falls Book 1), Linwood Barclay

Welcome to Promise Falls. The small town with a big secret. David Harwood is asked to check up on his cousin Marla, who's not been herself since losing her baby nearly a year ago.

But when he gets there, he finds blood on the door. Inside, Marla happily looks after a baby that isn't hers. She claims it was delivered 'by an angel', but David fears the worst.

His suspicions come true when a woman's dead body is found - with her own baby missing - making Marla the only suspect in the investigation. But David knows no matter how troubled she is: Marla isn't a murderer. Is someone lurking in the shadows? And how far will David go to protect his family?