The head of Mexico’s National Immigration Institute is set to face criminal charges over a fire at a detention center that killed 40 migrants unable to escape the flame, prosecutors announced Tuesday. Francisco Garduño failed to prevent the disaster last month just south of the U.S. border in Ciudad Juarez despite earlier warnings that the situation at Mexico’s migrant detention centers required improvement, the country’s federal Attorney General’s Office said. The tragedy highlighted a “pattern of irresponsibility,” prosecutors claimed mere hours after Mexican President Andrés Manuel López Obrador said a pair of guards seen fleeing the flames did not have the keys to unlock the cell door that prevented victims from escaping. “The door was closed, because the person who had the keys wasn’t there,” López Obrador said.