According to Hitchcock, using the resource of puzzling the audience is not the core of suspense. That is why he had never directed a puzzler or a whodunit. We can find evidence from this in an inteview he gave for the Hollywood Reporter in 1948, called 'Let'Em Play God', in which he clearly says: "I do not believe that puzzling the audience is the essence of suspense."
Regarding the difference between surprise and suspense, he explains that a surprise is something that produces a fright in the audice from a sudden. There is no expectation or tension before it because the scene has been created to take them by surprise. Otherwise, when a director creates suspense, the audience is prepared to what it will come, because you make them participate in the scene, you make them part of the situation.
