Anita's car is a 1941 Buick Special four-door touring sedan.
Dennis O'Keefe worked on this screenplay and was credited under the pseudonym of Jonathan Rix. When he arrived on set for the first day of filming he learned that all Christmas references were removed from the script. O'Keefe was adamant that Christmas was crucial to the film and refused to act in the film unless Christmas was put back into the production. The producer reversed his decision and Christmas was reinstated.
By the time Cover Up (1949) was released, Dennis O'Keefe had already appeared in Anthony Mann's T-Men (1947) and Raw Deal (1948), and his timing had already made him, as Robert Porfirio notes in Film Noir: The Encyclopedia, a "noir icon known for his fast-paced delivery." Notably, O'Keefe was one of the writers of Cover Up --- credited as Jonathan Rix --- which suggests he may have had a feel for writing dialogue as well as slinging it. In fact in his teens, O'Keefe started to write film scripts while attending college before becoming an actor.
First of three films for Dennis O'Keefe's production company --- Strand Productions. The other two are Without Honor (1949) and A Kiss for Corliss (1949).