The Woman in the Window (1944) on Netflix

Gotham College professor Wanley and his friends become obsessed with the portrait of a woman in the window next to the men's club. Wanley happens to meet the woman while admiring her portrait, and ends up in her apartment for talk and a bit of champagne. Her boyfriend bursts in and misinterprets Wanley's presence, whereupon a scuffle ensues and the boyfriend gets killed. In order to protect his reputation, the professor agrees to dump the body and help cover up the killing, but becomes increasingly suspect as the police uncover more and more clues and a blackmailer begins leaning on the woman.