Firewall

A body is found at a cash point, the apparent victim of a heart attack. Two teenage girls are arrested for the brutal murder of a cab driver. The girls confess to the crime, showing no remorse. Two open and shut cases. At first these two incidents seem to have nothing in common, but as Wallander delves deeper into the mystery of why the girls murdered the cab driver, he begins to unravel a plot much more involved complicated than he initially suspected. The two cases become one, and lead to a conspiracy that stretches beyond the borders of Sweden.

Three youngsters are shot dead whilst having a woodland picnic in fancy dress. The corpses are found, and a friend of the victims is also slain, having told Wallander that his workmate was really gay, and that he is a transvestite, and a wholly murderous one, who adds to his toll of dead by killing a further trio of innocents.