In the beginning when the murderers plunder a gold stash in a farm one of them grabs a gold bar with a glove and after a short look with naked eye and a gentle rub declares "solid gold". This examination is hardly enough to make such an assumption, especially when the handling of the gold bars suggests that they are lighter than they should be.
The police helicopter that picks up the agents has German registration D-HEBA. U.S. aircraft use prefix N.