Iron Cross (2009)

Joseph, a retired New York police officer and Holocaust survivor, travels to Nuremberg to visit his son Ronnie years after turning his back on him for rejecting a promising career in the NYPD and marrying a local artist, Anna. No sooner does Joseph attempt to heal the rift with Ronnie then he swears that living in the apartment above, under the false name of Shrager, is the now aging SS Commander who slaughtered his entire family during World War II. With little hope of seeing him stand trial, Joseph talks Ronnie into exacting justice - and vengeance - and together they set out to kill him.