Shrieker (1998)

Clark, a young Mathematics major, thinks she's found the best deal for student housing: a group of squatters residing in an abandoned hospital secretly. The quirky occupants let her into their community, provided she follow the rules, including not telling anyone about her living arrangements. All seems wonderful, until Clark discovers why the hospital was abandoned: in the 1940s, a series of murders were committed by a strange 'shrieking killer' who was never captured — and the discovery that someone is using the occult to resurrect the demonic 'Shrieker'.