Fallen (1998)

Decorated homicide detective John Hobbes (Denzel Washington) and his partner, Jonesy (John Goodman), have apprehended a demonic serial killer, been present at the killer's trial and witnessed his execution.

But when a new series of slayings are committed in the late killer's same peculiar style and Hobbes is eventually implicated, he must question his beliefs about the supernatural and face one overwhelming truth: pure evil is eternal and knows no bounds.