The Night Hunter : Anderson and Costello, Book 5(Anderson Costello‪)‬

Elvie McCulloch's sister Sophie has been missing for 57 days. She went out for a run – and never came home. Several young women in the area have disappeared in similar circumstances and Elvie's family fears the worst. Teaming up with retired detective Billy Hopkirk, Elvie determines to find out the truth. But as the pair alternately collaborate with and infuriate investigating police detectives Anderson and Costello, they find themselves up against a terrifying enemy. Someone they call ‘The Night Hunter.'