Dead Wrong by J.A. Jance

Juggling a family and a career is never easy-and it's becoming a real challenge for Sheriff Joanna Brady. Coping with the impending delivery of her second child as well as a staff shortage, the last things Joanna needs are two serious crimes. First, the body of an unidentified man is found in the desert, all of his fingers savagely severed. Following the scant clues, Joanna learns that the victim was an ex-con who had served twenty years in prison after confessing to the murder of his pregnant wife. During his last days he was seen following and photographing a young woman.