One Step Behind

S1, E3: Three teenagers are murdered on Midsummer's Eve, each with a bullet to the head; their bodies lie undiscovered for two months. As Wallander investigates, it becomes clear someone else has already been asking questions - Kalle Svedberg, one of Wallander's colleagues. But before Wallander can speak to him, Kalle is found dead in his flat, a bullet through his head.