The condition remains serious of a German police officer who suffered life-threatening injuries when a knife-wielding attacker targeted a gathering by the anti-Islam right-wing group Pax Europa in the city of Mannheim, police said Saturday. Police shot the so far unidentified attacker after he injured six people on Friday, with security sources telling dpa he suffered life-threatening injuries. Anti-terror investigators have taken over the case. Five participants in the Pax Europa rally were hurt and a policeman also suffered severe injuries when the attacker stabbed him in the back of the hea…