Martineau was a French police officer.
After Amalie Govier's death, Roz Forrester and Chris Cwej were taken in for questioning to Martineau. They convinced him to trust them and help in their investigation of the apparent abduction of children around the world. They went to question Monsieur Parmentier, whom they asked about the recent disappearance of the entire population of the village of Larochepot.
When Roz and Chris were trying to quickly get from France to Parmentier's factory in Bristol, Martineau recommended they contact his friend Emile Chevillon, who had a plane. (PROSE: Toy Soldiers)