Hitchcock loved this trope.

Take a guy who we all kind of like and set him up for a crime he seriously wouldn't touch with a ten-foot pole. Then set everyone—and we do mean everyone—against him, and let him spend the rest of the movie trying desperately to find the real killer before the cops swoop in and throw him in the slammer.

He used the idea in a number of his films, but in North by Northwest he absolutely outdid himself. He gave us a guy wrongfully accused of not just any old crime, but the murder of a UN official.

And the newspapers have a picture of him actually pulling the knife out of the guy's back.

It was the culmination of Hitchcock's Innocent Man Wronged notion…and in this case, it also worked to put some boogie in Roger Thornhill's step. He's a bit of an apathetic character, which Cary Grant was very good at playing. You get the sense that this guy never rushes with anything. It's just the way he rolls.

But put him on the front of every paper in the U.S. with "MURDERER" above his picture? Yeah, he's going to get to the bottom of the mystery awfully quick.