An aerial view of Belgian soccer side Beerschot’s stadium in Antwerp. Photo: Reuters/Belga/Diederick Ettema Belgian police are investigating a group of soccer fans who sang violently antisemitic songs following a match against a rival team. Dozens of supporters of the Antwerp-based Beerschot football club were caught on video singing in a cafe following their team’s 7-0 thrashing by top Brussels side Anderlecht on Monday night. Also heard was another Dutch import mocking the Holocaust, as the fans sang, “Dad was in the Gestapo, Mom was in the SS, Together they burned Jews, Because Jews burn best — Sieg Heil!” According...