This Rebel Breed (1960)
Combination of campy teen exploitation and serious drama. In what must be Los Angeles, the police send a couple of undercover cops to a high school in join the racially divided gangs. One guy is to get into the Anglo gang. Weirdly, they think it's a good idea to have the other guy play the role of a half-Black, half-Hispanic kid. (He's an Anglo actor in heavy makeup, the film's greatest embarrassment. The character's name is "Frank Serano," so maybe he's really supposed to be what he pretends to be, or at least Hispanic.) As you might expect, he's rejected by both the Black and Hispanic gangs. Of course, all the high school students appear to be about thirty years old.
The story revolves around the character played by pre-West Side Story Rita Moreno, who steals the film with a strong performance. In a plot device which anticipates that of the movie that won her an Oscar, she's in love with one of the Anglo guys. (In a powerful line, she tells him that she's tired of hiding their affair "like cats in the night.") Long story short, this decent fellow winds up getting killed by the nasty leader of the Anglo gang, who's also a drug pusher. (Yes, there's a "wild marijuana party" scene.) Moreno sets out to prove his guilt. (I'll give the film a few points for dealing honestly with the fact that she's pregnant by her murdered lover.)
One notable subplot involves "Wiggles," the girlfriend of the killer, played by a young and extremely curvaceous Dyan Cannon (back when she was still billed as "Diane.") In another example of awkward racial casting, the creep dumps her when he finds out that she's Black, passing as White. At least they didn't try to disguise Cannon's extreme Whiteness with makeup, but that makes this plot twist even more ludicrous.
It's worth noting that the version of this film I watched bore the new title The Black Rebels for its 1965 re-release. The Black gang is hardly in the film at all, so the new title is very misleading. They also added several brief sex scenes at random. No nudity, but lots of women in their underwear and some fondling and groping. They got the actor who played the Anglo cop to film a running gag where he walks in a door, sees what's going on, says "excuse me" and leaves. These sequences are really stupid, and badly disrupt a film which has some good points.