Existential Hitchcock

I have an idea for an entertaining essay about Hitchcock films, so I’m compiling a list. I’ve seen a few of them in my life, but I’m by no means an expert. Perhaps you’d like to help?

I’m particularly looking for films in which part of the suspense is related to whether or not the murder has/will actually occur(red). The existential quality of a murder, in other words. When do suspicions graduate into an actual crime?

Films I have so far are:

Rear Window
North by Northwest
Rope

I know there are more. Got a suggestion? Leave it in the comments!

Thanks.

Comment from Kira - 05/18/2011 at 18:42

Vertigo, kind of. Danger may or may not be present, which is dangerous.