From amazon:
Fourth in the Kurt Wallander series.

In the award-winning Sidetracked, Kurt Wallander is called to a nearby rapeseed field where a teenage girl has been loitering all day long. He arrives just in time to watch her douse herself in gasoline and set herself aflame. The next day he is called to a beach where Sweden’s former Minister of Justice has been axed to death and scalped. The murder has the obvious markings of a demented serial killer, and Wallander is frantic to find him before he strikes again. But his investigation is beset with a handful of obstacles—a department distracted by the threat of impending cutbacks and the frivolity of World Cup soccer, a tenuous long-distance relationship with a murdered policeman’s widow, and the unshakably haunting preoccupation with the young girl who set herself on fire. Fascinating and astute, Sidetracked is a compelling mystery enhanced by keen social awareness.