Frenzy: the falsely-accused man, 1
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Above: Richard Blaney is introduced via a match cut that associates him with the necktie murders of which he will eventually be accused.

Below: The early scenes of the movie, before the actual murderer is revealed, are devoted setting up Blaney as a man with a violent temper and a streak of misogyny.

Blaney's friendship with Bob Rusk sets up another Doppelganger motif in a Hitchcock film. Like Bruno in Strangers on a Train, Rusk murders Blaney's ex-wife shortly after Blaney has been observed verbally abusing her.

Blaney is in the foreground as the lawyer and doctor discuss the necktie murderer's pathology: "We haven't had a good juicy series of sex murders since Christie, and they're so good for the tourist trade."

Even after the audience knows who the murderer is, Blaney is visually associated with the crimes, and with violence against women.
Blaney's arrest provides the most explicit visual equivalent of Hitchcock's fear of jail cells and the "clanging door" (according to him, a memory from his childhood).