Greg Cox wrote:
("Only Hitchcock would be bold enough to kill off the heroine a third of the way through the movie!"--despite the fact that this was straight from the novel.)
Bloch has certainly been overlooked in appreciations of the movie (a fate that has befallen most of the authors of material adapted by Hitchcock to the screen, unfortunately). Even the screenwriters he employed have struggled for recognition under the great behemoth of Hitchcock's media personality.
On this point, however, I think Hitchcock deserves some credit, both for choosing to adapt Bloch's novel and staying true to it's twist where the heroine is murdered part way through. That was bold move for the novel, but an even bolder move for the movies -- especially in a 1960 studio production. Bloch deserves all the credit for coming up with it, though.