Jean Mortier, who used the pseudonym Jem, was a Belgian art teacher and comics artist. He made 'Pol et Rico' for the weekly magazine Pat, as well as 'Marc Le Résistant' for Fulgor of Éditions Artima (1955-1958). In 1957, he began the silent family series 'Les Malheurs de Charlie' (later only 'Charlie') in La Libre Belgique, which ran until 1969.
For the same paper, he made the police series 'Jean Valfort' from 1959. His name also appeared in the magazines Tintin ('Les aventures de Stany' in 1961 and some short stories in 1962) and Spirou (a micro story and advertisement strips), as well as in the Héroic Albums series.