The preacher is a charlatan, a huckster. And he knows it.

But Rev. Cotton Marcus (Patrick Fabian) is reconciled to that. He went into the family business, became a compelling performer and ekes out a living in his corner of Louisiana.

As a side business, he’s taken up his dad’s exorcism practice, “because if you believe in God, you have to believe in demons.” Since he doesn’t believe in either, it’s not a big deal for him to visit the gullible, put on a show and chase away demons from the possessed — for a fee.

He’s followed around by a film crew as he talks frankly, mockingly, about his work and “the business.” The idea, he says, is to “expose exorcism for the scam it really is.” After this, he’ll change careers. “Maybe I’ll sell real estate.”

“The Last Exorcism” is a “Blair Exorcist Project” about Cotton’s trip into the bayou — or that Hollywood corner of it where everybody is a rube even if nobody has an authentic accent — to exorcise a teenage girl named Nell (Ashley Bell). It’s about what happens when a non-believer is confronted with evidence that his parlor tricks are not what’s causing the lights to flicker and moans to rumble out of the walls.

Daniel Stamm’s film (script by Huck Botko and Andrew Gurland) is a modestly chilling, drawn-out affair in which the characters and possible “scientific explanations” are more interesting than its predictable final destination. Bell is a perfectly demonic presence. Fabian is absolutely credible as a man who will not accept the supernatural, and who isn’t shy about hustling the hicks.

But when he sees he can’t help this child, he pushes her dad (Louis Herthum) into taking her to a doctor. He reaches out to her creepy brother (Caleb Landry Jones), despite the boy’s constant threats. He tries to reason this out. He tries to do the right thing. He’s a charlatan with a conscience.

Stamm’s film would have benefited greatly from a more compact telling of the story, narrowing the focus, hard as that might be, to a day and then a long, chilling night (this takes place over a few days). There’s humor in the unseen camera operator’s fear, in the protective instincts of the director (Iris Bahr), who is ready to involve social services in whatever is going on here, a modern day big city solution for a backward, superstitious community’s problem.

But strip it down to its basics and “The Last Exorcism,” which occasionally breaks out of the documentary “found footage” format (music wells up on the soundtrack), will make the hairs on the back of your head stand up. Its grisly violence and ridicule-religion tone make it sort of the anti-“Exorcism of Emily Rose.” And this hustle isn’t slapped with a “Based on a True Story” come-on.

Film focus

WHAT: “The Last Exorcism”

RATING: 2 stars

RATED: PG-13 for disturbing violent content and terror, some sexual references and thematic material

RUNNING TIME: 1 hour, 25 minutes

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