German authorities have offered a €20,000 ($24,000) reward for information leading to the arrest of a man believed to be responsible for Wednesday's bombing in Cologne which injured 22 people. The blast, which spewed nails along a busy shopping street in a predominately Turkish immigrant neighborhood, has not been immediately linked to political or terrorist motives. German Interior Minister Otto Schily has said it was probably the work of common criminals. Cologne police have put up a want-ad for an unidentified man, age about 30, seen with a bicycle outside a hair salon shortly before the bomb exploded in front of it. He was wearing a baseball cap and carrying a backpack. Police said they offered the reward in the hopes of receiving tips about the suspect. They admitted they had no other leads, but had not completely ruled out an anti-foreigner attack or crime gang rivalries or even political terrorism.