The Traitor Within (movie, 1942)

In this drama, a truck driver begins wooing a young woman who still lives with her father who constantly brags how he, not the town mayor, was responsible for catching a regiment of Germans during WW I. Unfortunately, no one in town takes him seriously. Later the daughter meets a German immigrant who confirms her father's claim. She then convinces her boy friend to use this information to blackmail the mayor into giving him a new truck and some extra amenities lest he tell the truth.