Serial Killer hiding in Movie theater (kills cop)

Tough one, cause it’s neither “Popcorn” nor “Angustia”: Horror/Slasher/Serial killer movie from mid-80s. Maniacal killer escapes from mental ward and hides out in a movie theater. Patrons and employees are killed one-by-one. The police are called and the lead investigator is an African-American gentleman who decides to sit and think about the case in the middle of the empty theater. It is daytime. When evening comes, an usher finds the detective still sitting there. The usher approaches and taps him on the shoulder. The detective is dead. The final scenes take place in an attic above the theater – on a walkway with tight crawl space.