In a Lonely Place (1950)

Dixon Steele is a Hollywood screenwriter who has not had a hit movie in years, his best screenwriting days most-likely behind him. His longtime agent, Mel Lippman, is arguably his best friend despite their sometimes rocky relationship. Mel suggests that he read an acquaintance's novel as possible source material for a movie, Mel giving Dixon overnight to go through the material before making a decision. By morning, Dixon's life takes a turn as he is called to the police station by Detective Brub Nicolai, an old friend from their military days, as a possible suspect in the murder of a young woman who Dixon had spent some time with the evening before. Dixon ends up with an alibi in the form of Lauren Gray, a relatively new neighbor who lives in the apartment across the courtyard from him, she who willingly provides this alibi, despite not knowing him, because she states she likes the look of his face. Dixon in turn is smitten with her as well, the two who embark on a relationship. Lauren, an aspiring actress, ends up inspiring Dixon to do the best writing he has done in years. Nicolai's boss, Captain Lochner, still believes that there is merit in pursuing Dixon as a suspect regardless of the alibi, in large part due to Dixon's past history of a violent temper and violence, of which Lauren is initially unaware. Regardless of if Lauren may have ulterior motives in providing that alibi and entering into the relationship with Dixon, she may regret her decision if Dixon does display that violence, which often pops up in the emotion of his writing, or worse if he really is the murderer.

IMDb: https://www.imdb.com/title/tt0042593