Sandström served as Deputy Police Commissioner in Stockholm from 1979 to 1987. In 1987, Sandström was appointed chief of the Swedish Security Service (RPS/Säk, later Säpo) during the very turbulent time after the assassination of Prime Minister Olof Palme. He left the post in 1989 in the aftermath of the Ebbe Carlsson affair and the Stig Bergling-affair and then became Head of Department at the Swedish National Police Board where he was responsible for coordinating the police work in connection with the UEFA Euro 1992. He was then head of the Police Operations Department at the Police Authority in Stockholm County before ending his career as Deputy County Police Commissioner in Stockholm County from 2000 to 2003.