Police have arrested a man in Marseille, France, who is suspected of killing three people last week in the Jewish Museum in Brussels, Belgium, Belgian federal magistrate Wenke Roggen said Sunday. The suspect is identified as 29-year-old Frenchman Mehdi Nemmouche, who recently spent a year in Syria and is a radicalized Islamist, the chief prosecutor of Paris said at a news conference Sunday. Francois Molins said Nemmouche, who has a criminal history that included a five-year prison stint, was...