Karl Martino Widmark (born 19 March 1961) is a Swedish children's writer and teacher. His books about LasseMaja junior mysteries, in English named The Whodunit Detective Agency, have been translated from Swedish into 34 languages. Eight of them have been translated into English and published by Grosset and Dunlap. Several of his books about the Whodunit Detective Agency have been adapted to film in Sweden, and they have also been made into board games, theater and video games. Martin Widmark was born in Sturefors and grew up in Linköping, but has lived in Stockholm since the 1980s. .
https://en.wikipedia.org/wiki/Martin_Widmark