Sidney Poitier returns for his third outing as Virgil Tibbs, as the San Francisco detective looks into a clandestine war between a group of young street vigilantes and a heroin-smuggling ring. When his sympathies for the citizen brigade land him on suspension, Tibbs finds his hands free to break the drug dealers for good. Gritty urban actioner co-stars Barbara McNair, Raul Julia, Sheree North, Allen Garfield. 105 min. Widescreen; Soundtrack: English Dolby Digital mono; theatrical trailers.