Police lieutenant Nyman is murdered in his hospital bed and Martin Beck and his colleagues have another murder to solve. They discover that Nyman was a very tough policeman who received several complaints about his methods. His partner Hult defends him against these accusations, while Nyman's widow explains that Hult was the only one outside of the family who knew where Nyman was hospitalized. It becomes obvious to Beck, that a lot of people wanted Nyman dead, but he is not the only one targeted. Soon a sniper kills policemen from a roof in central Stockholm.