It takes place before the war breaks out.
The movie is Man Hunt (1941) -- the link is to an imdb.com Internet page.
Walter Pidgeon stars as Captain Alan Thorndike, a big game hunter. He takes on the challenge of "stalking" Hitler to see if he could kill him -- if he wanted to.
Then things get really interesting after that in his life, and he becomes a fugitive -- even though he never intended to "shoot Hitler"...
Yeah, I saw the movie (in 1941 too) and have always wondered “what if?”
I also remember a “60 Minutes” story about police snipers that opened with an off-camera voice saying “there are people who need to be shot.”
If we had known in 1939 what we know now, anyone who had ‘offed’ Hitler would be a hero. For that matter, many of our Revolutionary War heros are still considered villians in Britain. Future history is a very difficult subject and one that no one can really know. Perhaps this man who shot Tiller will be hailed as a hero in the future. Right now though, he’s in deep doo-doo.