'Battle With the Devil': 'Nightline' Anchor Terry Moran Describes Meeting Those Who Believe Satan Tortured Them "Nightline's" Terry Moran talked with people who believe they have faced Satan.

July 19, 2011 -- It's not your ordinary Sunday service.

In a small church just outside Buffalo, N.Y., people are retching and coughing up into paper bags. A few are incessantly, forcefully, weirdly yawning. An 8-year-old boy is tackled and pinned to the ground as he yells out, "Get off of me!" Someone gets hit in the back of the head by a large man erupting around the room in a screaming fit. There is much fervent praying and quiet weeping.

There is something else going on here, too. In the belief of these Christians at the Agape Bible Fellowship in East Aurora, New York, a "deliverance ministry," there is a triumph unfolding before our cameras -- a triumph over Satan.

"When we begin to cast that spirit out, there is manifestation," said Pastor John Goguen, a graduate of the Dallas Theological Seminary who founded Agape 22 years ago. "People have to humble themselves, and some people can't get beyond what to them looks like play acting -- it looks foolish. But there's a verse in the Bible where Paul the apostle says that God uses the foolish things of the world, things that look foolish, to confound the wise."

Satan has fallen out of fashion for many Americans, even for many Christians. Belief in the existence of the devil as an actual living spirit wanes in this country with each passing year. To many people, Satan is, at most, a symbol or metaphor for the malignancy that stalks human history, a way of thinking about our species' seemingly boundless capacity for cruelty. For a lot of other people, the devil is merely a fantasy of deluded minds. A tired Hollywood joke.

Believers like to quote the old line that the devil's greatest trick was convincing people that he does not exist. But every culture in human history has believed in evil spirits. For better or worse, this belief, and the figure of Satan himself, is part of the human story, a story that continues today, in our own time, in our own country.

In our program, "Beyond Belief: Battle with the Devil," we set out to discover how the battle against Satan is being carried out in America, for those who believe that the Prince of Darkness and Author of All Lies is a real presence in the world, a real threat in their lives.

From the Agape church in New York to an exorcism conducted in California, from a Christian ministry attempting to rescue women from the sex trade in Las Vegas to a training class for exorcists in Rome, from Times Square in New York to the "Amityville Horror" house -- we met people who sincerely believe they are locked in combat with the devil. It has been an astonishing journey.

We don't set out to prove or disprove the existence of Satan; we simply want to respect the authenticity of the beliefs of the people we met. What we hope we've done is shine a light into a world of spiritual warfare that goes on all around us, and report the amazing experiences of people who are convinced they have struggled not just with the moral reality of evil in their lives, but with a powerful and terrifying supernatural being who promotes and generates that evil: The devil.

And that they have triumphed over him with the most powerful spiritual force of all: Love.

We hope you'll watch.

Tune into "Primetime Nightline: Beyond Belief's" special, "Battle With the Devil," airing Wednesday, July 20 at 10 p.m. ET