A manhunt was under way in Berlin on Thursday after a man left behind a bag full of explosives at a train station following a routine police stop. Investigators are continuing to search for the man, who fled the scene at Neukölln train station in southern Berlin after being stopped by police on Wednesday afternoon. The explosive material was then safely detonated by police in a nearby park. German media reported that the material found in the man’s bag was triacetone triperoxide (TATP), citing security sources in the German capital. The explosive is widely used by criminals targeting cash mach…