A man who attacked two children with a knife in the western German city of Duisburg was stopped and disarmed by his own father, police sources told dpa on Thursday. The 69-year-old father held down his 21-year-old son until police arrived. The children are in hospital and their lives are not in danger. The son had stabbed the 9-year-old girl and 10-year-old boy before a passer-by shouted and threw a torch at him. The attacker ran off before being confronted by his father, while the two injured children managed to reach a nearby school. The son told his father that information on his mobile pho…