The massacre was intentional, as substantiated by historian Jean-Luc Einaudi, who won a trial against Papon in 1999 (Papon had been convicted in 1998 of crimes against humanity for his role under the Vichy collaborationist regime during World War II). Official documentation and eyewitness accounts within the Paris police department suggest that Papon directed the massacre himself. Police records show that he called for officers in one station to be "subversive" in quelling the demonstrations, and assured them protection from prosecution if they participated.