Factual error: There's a scene when Barbara Stanwyck hides behind an open door to avoid beeing seen by Edward G.Robinson leaving Fred MacMurray`s apartment. To make this possible the apartment door opens outside into the corridor, which is an elegant solution for this situation in the movie. But in the real world no apartment door would open by swinging into the corridor because this would give a visitor standing there a punch on the nose when the resident opens the door.
Factual error: When Bruno is on his way to Union Station, he's heading on a bridge away from the Lincoln Memorial, which means he's leaving Washington D.C. for Arlington, Virginia, or in other words, he's going the wrong way.
Factual error: After Harry Powell disappears from in front of Ms. Cooper's yard, a barn owl swoops down on a rabbit. We can hear the owl's wings flap even though barn owls make no noise when they fly.
Factual error: Joseph Cotton spends the second half of the movie trying to get out of Canada, but in the scene at The Cave of the Winds with Jean Peters, he must have forgotten that he was already on the American side of the falls. (00:54:00)
Factual error: At the end of the movie, Joe Gillis is shot twice in the back and once in the chest before falling dead into a swimming pool. However, no blood from the wounds is ever seen in the pool, even after his body has been floating in it overnight.
Factual error: At the drive-in movie theater, Cody orders his wife to turn off the speaker. She twists the knob in the wrong direction (to the right, which would have increased the volume instead), but somehow the sound turns off anyway. (00:29:00)
Factual error: All the light switches are the wrong way round for UK, where up is off. Presumably because film sets were in USA.
Factual error: In the opening credits, it says that the Knights Templar of Malta paid tribute to the King of Spain with the Falcon in 1539. The Knights that were in Malta were the Knights Hospitallers of the Order of St. John of Jerusalem. They mixed with the order of the Knights Templar, which went out of existence in 1314 and has also been founded in Jerusalem. They had nothing to do with Malta.