he must have scouted the area multiple times before, in person or digitally. eventually they will get him from the traces unless there was a network of people doing the scouting and him only doing the hit. the surveillance state will get him given a long enough time. entering the country with a fake passport, doing the hit and then fleeing the country right after is the only way for an epic assassination to stay unpunished and that's how all the infamous mossad assassinations took place.
Germany