Questions about the religious background of Andreas Lubitz, the Germanwings pilot who investigators said deliberately crashed a plane in the French Alps this week, killing all on board, have sparked outrage and debate about whether such information is relevant to the investigation. When a reporter asked French Prosecutor Brice Robin of Marseille, during a news conference Thursday, whether he knew Lubitz’s religion, Robin said he did not know and added, “I don’t think that’s where the answer to this lies.” The question suggested that Lubitz’s religious background was relevant to the investigation behind the pilot’s alleged deliberate downing of Germanwings...