On Reddit I stumbled across this old screen test of Deborah Harry auditioning for the crime mystery movie Union City, which was released in 1980 to lukewarm reviews. She got the part as the leading actress, with a smaller role going to Pat Benatar.
Here's the plot, from Wikipedia:
Harlan (Lipscomb) is a repressed, uptight accountant living in an apartment block with his beautiful, neglected wife Lillian (Harry). He becomes obsessed with discovering who is drinking from the milk bottles left outside his apartment every morning, so he ties some cord to a bottle which will alert him when it's taken, and through this he finds the culprit to be a homeless war veteran (Sam McMurray). The vagrant apologises but the obsessive Harlan attacks him, knocking him down and seemingly cracking his skull. In a panic he hides the body behind the folding bed in another vacant apartment opposite his own.
Harlan's behaviour becomes ever more irrational, driving Lillian away from him and into the arms of building supervisor Larry Longacre (McGill); he believes another deranged resident known as the Contessa (Irina Maleeva) is planning to run away with him and puts potential residents off the room where he hid the vagrant's body with his bizarre behaviour.
However, eventually a young couple of newly-weds, Alphonse (Tony Azito) and Jeanette (Pat Benatar) Flourescu move in. Harlan attempts to dissaude Alphonse from opening the bed but is unsuccessful. Alphonse looks at the bloody but empty bed as a terrified Harlan throws himself through the apartment to his death on the street below. A crowd gathers around his body, watched briefly by the disinterested vagrant, alive with his head bandaged.
I've never seen the film, but love the trailer below (was that really 1980?!) and plan on watching the movie asap.