Since the filming times were so long, everybody on the set tried their best to avoid any mistakes. At one point in the movie, during the first take scene, the camera dolly accidentally ran over and broke a cameraman's foot, but to keep filming, he was gagged and dragged off the soundstage. Another time, a woman puts her glass down but misses the table. A stagehand had to rush up and catch it before the glass hit the ground. Both parts are used in the final cut.
This movie was unavailable for three decades because its rights (together with four other movies of the same period) were bought back by Sir Alfred Hitchcock and left as part of his legacy to his daughter Patricia Hitchcock. They've been known for a long time as the infamous "five lost Hitchcocks" amongst movie buffs, and were re-released in theaters around 1984 after a thirty-year absence. The others are La finestra sul cortile (1954), L'uomo che sapeva troppo (1956), La congiura degli innocenti (1955), and La donna che visse due volte (1958).
The theatrical trailer features footage shot specifically for the advertisement that takes place before the beginning of the movie. David (the victim) sits on a park bench and speaks with Janet before leaving to meet Brandon and Phillip. James Stewart narrates the sequence, noting that's the last time Janet and the audience would see him alive.
This movie was banned in several American cities because of the implied homosexuality of Phillip (Farley Granger) and Brandon (John Dall).
Alfred Hitchcock: appears, though barely if at all recognizable, walking down the street during the opening credits at around 2 mins as one of two pedestrians walking up a sidewalk holding a newspaper. The neon sign advertises "Reduco", the same fictional weight-loss product that Hitchcock advertised in his famous newspaper ad cameo in I prigionieri dell'oceano (1944).
Alfred Hitchcock: [Identifying with the killer] Throughout the movie, Brandon and Philip are at risk of exposure.