Just One Evil Act by Elizabeth George
The aristocratic D.I. Thomas Lynley and the slightly grubby Det. Sgt. Barbara Havers make an unusual but highly effective investigative team, but in the 18th novel in Elizabeth George’s Scotland Yard series Havers deliberately excludes her boss and ally from her activities.
In Just One Evil Act, the daughter of Havers’ friend and neighbor Azhar is kidnapped. When Azhar asks for help in recovering his child, Barbara leaps to his aid, breaking a number of police protocols in the process. But the kidnapping is just the beginning of a series of events that make even loyal Barbara question Azhar’s honesty.
Before Havers’ reckless (and not entirely believable) behavior leads to total disaster, D.I. Lynley (as always) comes to her rescue. A good addition to this popular series, but at 736 pages, it would have benefited from more rigorous editing.