Milton Arbogast is a detective hired to recover $40,000 stolen by Marion Crane from her employer in Phoenix, Arizona. After following Marion's trail to Fairvale, where her lover Sam Loomis owns a hardware store, he finds she never made it to the town.
Arbogast eventually discovers that Marion stayed under an assumed name at the Bates Motel, situated near Fairvale. The owner, Norman Bates, seems nervous and might be hiding information, so Arbogast decides to return to the house above the motel in order to question Norman's mother, Norma Bates.
As he sneaks into the house and climbs up the stairs, Arbogast is attacked by an old woman who slashes a knife across his face. He tumbles backwards down the stairs, collapsing in the hallway, and his attacker repeatedly stabs him. Norman then disposes of the detective's body in a nearby swamp, in the same way he previously disposed of Marion's body after she too was murdered at the motel.
Arbogast's body is eventually recovered after Sam, working with Marion's sister Lila Crane, exposes Norman Bates as the actual murderer.
The reason she was hired was that Hitch was particularly worried that the audience was going to see through the whole thing. Remember, this scene comes a little more than halfway through the picture. In order to strengthen the illusion, he engaged a woman who was very small and, physically, totally unlike anyone else in the picture.
Although a number of options were considered for how to film Balsam tumbling backwards down the stairs, Hitchcock used the relatively simply method of shooting a background plate of a descent down the staircase and then had the actor sit in a gimbal chair in front of rear-projection screen. Balsam simply leaned back and flailed his arms as if tumbling backwards.
Although there has been much discussion — and controversy — about Saul Bass's contributions to the film, particularly in the shower scene murder sequence, is it worth noting that Hitchcock discarded Bass's storyboards for the murder of Arbogast as being too clichéd.
Notes & References
- Alfred Hitchcock and the Making of Psycho (1990) by Stephen Rebello, chapter 7: Arbogast Meets Mother