A knife-wielding attacker in the German city of Mannheim injured six people on Friday when he targeted a gathering by the anti-Islam right-wing group Pax Europa. Police shot the so far unidentified attacker, with security sources telling dpa he suffered life-threatening injuries. Anti-terror investigators have taken over the case. Five Pax Europa members were hurt and a policeman also suffered severe injuries when the attacker stabbed him in the back of the head several times, authorities said. All of the injured were taken to hospital and some had to undergo emergency surgery. Pax Europa boar…