- This article is about the film version of the character. For the Bates Motel version, see Sam Loomis (Bates Motel).
Loomis was in love with Marion Crane and frequently visited her in Phoenix, Arizona. They were first seen finishing up a sexual encounter in a flophouse. Though Sam proposed the idea of marrying her, she was unsure of this move.
A large reason behind Marion's ambivalence was that Sam admitted he had taken on moderate to heavy debt to keep his hardware store afloat during recessions, and his money problems were not being helped by alimony payments to his first wife. This unknowingly set tragic events in motion: when returning to work, Marion embezzled from her boss after a wealthy customer, Tom Cassidy, made payment in full for $40,000. Marion absconded with the money, thinking she could use it to retire Sam's debts and he would be able to give her a happy marriage.
Following Marion's disappearance, Sam and Marion's sister, Lila, hired a private investigator, Milton Arbogast. Arbogast later called them from the Bate Motel, telling them that he had met Norman Bates, who lived in a house by the motel with his mother.
After Arbogast failed to give Sam and Lila more information, Sam visited the motel, looking for him, but saw nobody but Bates' mother, who gave him no response.
Sam and Lila then went to the local sheriff, Al Chambers, who informed them that Mrs. Bates had been dead for ten years after committing suicide and suggested that Arbogast had deceived them and made off with the $40,000 that was in Marion's possession.
Unsatisfied with this explanation, Sam and Lila went to the motel, acting as husband and wife. As Sam distracted Norman, Lila investigated the house. Becoming suspicious, Norman incapacitated Sam and rushed into the house.
Sam soon came to Lila's rescue, tackling Norman – who was dressed as his mother and wielding a knife – before he could successfully attack Lila.
At a local courthouse. Dr. Fred Richman explained that Norman had murdered his mother years before and had developed a split personality based on his mother. This "Mother" personality would commit murder, Marion and Arbogast being two of his victims.