Per Fredrik Wahlöö (5 August 1926 – 22 June 1975), often identified in English translations as Peter Wahloo – was a Swedish author. He is perhaps best known for collaborative work with his partner Maj Sjöwall on a series of ten novels about the exploits of Martin Beck, a police detective in Stockholm, published between 1965 and 1975. The fourth of the Beck novels, Den skrattande polisen, was published in 1968; a translation of this novel, The Laughing Policeman, won an Edgar Allan Poe Award for Best Novel from the Mystery Writers of America in 1971.
https://en.wikipedia.org/wiki/Per_Wahl%C3%B6%C3%B6