WHAT'S ANNOYING about "The Believers" is its few good moments of suspense. It means you can't dismiss it entirely. John Schlesinger, who directed "Midnight Cowboy" and "Marathon Man," knows how to weave edge-of-the-seat tension. But Mark Frost's screenplay, based on Nicholas Conde's occult mystery novel "The Religion," is a haphazard affair of implausibility and pseudo-Voodoo.

Martin Sheen, a respectable talent who needs to learn how to pick pictures, tries hard to bring human presence to a rather silly tale. He's Cal Jamison, a psychologist whose wife has died in an accident involving a faulty coffeemaker and spilled milk. The death appears to have no bearing on the film, except to get Sheen from Minneapolis to New York. Somebody liked the idea of a killer Mr. Coffee.

Escaping the freak horror of his wife's death, Jamison and his young son Chris (Harley Cross) arrive in New York only to find that young boys -- about Chris' age -- are being regularly carved up, cult-style.

Jamison now works as a shrink for the New York City police, and interviews Tom Lopez (Jimmy Smits), a superstitious Latino officer who's cracking up because, he says, he's on Their list. Before Lopez gets it (snakes in the gut; don't ask), he tips Jamison to a group of fanatics who appear to have taken "Rosemary's Baby" to heart. They believe in Santeria, an ancient dark religion with African/Caribbean roots that -- among many things -- apparently involves child sacrifice.

An African cultist whose eyes go kinda inside-out when he hears drum beats puts the hex on Jamison's new girlfriend Jessica (Helen Shaver), as well as his ally, Police Lt. Sean McTaggert (Robert Loggia). Jamison has to save his son and himself.

Sometimes, "Believers" achieves the pervading paranoia-inducing mood it aims for, mostly because the plot is so bloody vague, and Schlesinger fills the film with relics, crucifixes, flower petals and -- you know -- symbols. But the film foreshadows elements that never reappear. Chris seems to have supernatural powers, but they apparently take the rest of the movie off. And you expect Jamison's late wife to return from the dead, "Don't Look Now" style. She doesn't. Chris has an Indian doll that threatens to be significant -- but no, it's just an Indian doll. There are enough of these red herrings to feed 40 Swedes. The more you discover in "Believers," the more you realize you're watching glorified mumbo-jumbo. THE BELIEVERS (R) -- At the Uptown and area theaters.