A pipe bomb that went off last Wednesday in a Turkish immigrant neighborhood in the western city of Cologne was detonated by remote control, investigators said. The bomb, a gas cylinder loaded with gunpowder and nails, was likely in a backpack strapped to the back of a bicycle. Police are now looking for a man in his 30s with closely cropped blond hair who witnesses say left the bicycle in front of a hair salon just minutes before the bomb exploded. Police came to the conclusion that the device was remotely triggered after finding fragments in the debris, although authorities will not say what exactly was used. The bomb destroyed the hair salon and a neighboring pizzeria and injured 22 people. Police are offering a €20,000 ($24,000) reward for any information that leads to an arrest in the case.