Another plot hole
Why didn't the police search the theater after the fire scene? They saw Michael and Sarah go backstage. It would not be hard to find them among the costumes.
shareHitchcock would say: "Don't be droll"(his usual way of deflecting such on-point questions.)
Perhaps the secret police thought the two had escaped through the alley outside..on the run..more logical than "staying at the scene."
A cursory glance at even an open costume box would reveal only the costumes on top, not Michael and Sarah under them.
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