Sheriff Daniel H. Edwards of Tangipahoa said that as many as 25 children -- about evenly split between boys and girls -- might have been involved in sex acts at the youth center, in cars and in the homes of at least two of those charged. The abuse seems to have begun in 1999, he said, and stopped occurring on the church grounds after 2003.

"But nobody really believes that they just stopped abusing kids," Sheriff Edwards said.

Tangipahoa and surrounding parishes are fervently religious, and worshipers at other churches are wondering how something so troubling could have occurred.

"It has definitely affected my customers," said Diane Pepitone, owner of Heavenly Gifts Christian Bookstore. "The general consensus is, if anything like this can happen in a place like Ponchatoula, with all the churches we have, it can happen anywhere."

Ponchatoula was in the midst of its annual Strawberry Festival when Ms. Bernard called the sheriff. She was reluctant to discuss specifics, the sheriff said. "We'd call her and she'd say, oh, the dog's barking or somebody's knocking on my door right now, I'll call you back," Sheriff Edwards said. Two weekends ago, she began to name names.

The next day, the younger Louis Lamonica walked into the sheriff's office in neighboring Livingston Parish, where he lives, and proceeded to describe all manner of sexual offenses.

"He didn't come to turn himself in, he came to talk with us," said Stan Carpenter, the detective supervisor in Livingston Parish.

Mr. Lamonica, 45, matter-of-factly told them of having sex with at least two boys, from the time they were 4 until they were 12 or 13, as well as having sex with a dog, Mr. Carpenter said, adding that Mr. Lamonica did not act as though he was confessing to crimes. He was just trying to be helpful.