"The Boys Next Door" is just another exploitation movie about murderous nuts -- exactly what you wouldn't expect from Penelope Spheeris, the director of "Suburbia."

The thesis: The psychopaths who regularly pop up in the headlines used to be the Boys Next Door -- specifically, Roy (Maxwell Caulfield) and Bo (Charlie Sheen). They've just graduated from high school and decide to spend a weekend in sunny Los Angeles before beginning what promises to be 30 years at a drill press at the local factory.

So they hop in Roy's Plymouth Road Runner, and that's when the, uh, fun begins. Roy has all this anger, and somehow missed the section in the Frommer guide about leaving it at home while traveling. Beating the stuffings out of a gas station attendant with a crowbar, mauling and shooting a homosexual with his own .38, then taking the .38 and plugging two lovers necking in a convertible -- these things will throw a wet blanket on anyone's vacation.

"Y'know, you have very negative energy," says Angie (Patti D'Arbanville), a barfly who takes the boys home. And you think, boy, are you in for a surprise.

Spheeris begins the movie with a montage of photographs of everyone from Son of Sam to the Hillside Strangler, over which play snippets of the usual reactions, from psychologists and next-door neighbors ("He was so quiet. I'd never expect this from him"). It's the usual mumbo jumbo, yet it sets us up for something different; alas, no. The script (by Glen Morgan and James Wong) busily exculpates Roy, listing in dreary succession: (a) his loveless home life, (b) his exclusion by the "in group" at school, (c) his bleak prospects for the future . . . oh, you get the point.

And Roy isn't the boy next door at all; the way Caulfield plays him, hulking around, arms heavy, hair hiding his forehead, he's closer to the dark side of Steve Balboni. Sheen gives an attractive performance -- he's all edges, and he has some of the quizzical intensity of Daffy Duck in a bind. He's the boy next door, the one you identify with, and of course, the movie does everything to distance him from the murders. He participates only reluctantly, tries to call Roy off -- so what's left of the thesis?

The color is lush (the streets at night, for example, are lime green), the sound track (by The Cramps, Code Blue, et al.) loud, the violence meticulously edited to the music. Thus, a movie that tells us little about killers, much about movies about killers -- and how not to make them.

The Boys Next Door, at area theaters, is rated R, and contains considerable violence and profanity and sexual situations.