OT Reuters on Cologne blast Bomb blast injures 12 in Cologne Wed 9 June, 2004 17:15 BERLIN (Reuters) - An explosion in a building in the German city of Cologne that injured up to 12 people was caused by a bomb, German police say. "We are assuming it was an attack," a police spokesman said. He said there were no indications of a motive and no warning was given. Fire services earlier said the blast in a three-storey residential and business building on Wednesday injured up to 12 people, four seriously. N-TV television reported earlier that there was speculation the blast was an attack of some kind on a hairdresser's shop.