It later transpired that the group had been infiltrated by a Belgian collaborator posing as "Captain Jackson", who claimed to be a Canadian airman; the infiltrator's real name was Prosper Dezitter. He might have helped plan the slaying of Colin in order to gain Demonceau's confidence and thus net as many Resistance and other people in hiding as possible. Fraiteur, Demonceau and many fellow members of the Resistance were later executed by the Germans at Breendonk. After the war, Dezitter was arrested in Germany, extradited, condemned to death, and shot by a firing squad at Ixelles on 17 September 1948.