ARSHALL, Tex. — From its founding in 1987, the Evangelical Lutheran Church in America, which puts its membership at more than 5.3 million, has earned praise for its "zero tolerance" approach to sexual misconduct among its clergy.

After adopting a prevention strategy a decade ago, which its regional branches shaped into policies for handling abuse complaints, the national church dedicated a staff member solely to the issue, and in 1996, it published a 62-page book to educate its congregations on the subject. Bishops, pastors and seminarians now undergo training.

"The word has gone out in this church that clergy sexual abuse is not to be tolerated," a 1998 church study stated.

Yet abuse still occurs. In a case every bit as disturbing as those roiling the Roman Catholic Church, a former Lutheran minister from this small East Texas city has pleaded guilty to federal child pornography charges and faces state charges of sexually assaulting a teenage boy. A civil lawsuit accuses Lutheran officials of ignoring past incidents involving the pastor, Gerald Patrick Thomas Jr., and says they bear responsibility for his actions, a claim the national church strongly rejects.

To some extent, clerical sexual abuse exists in every religious group, experts say. But quantifying the problem is almost impossible.

A handful of studies compiled by the Center for the Prevention of Sexual and Domestic Violence, some more than a decade old, suggest that up to 15 percent of clergy members in all religious groups have engaged in some inappropriate conduct, whether a stolen kiss or full-fledged sexual abuse. But few authoritative statistics are available on the number and type of complaints, and what information churches collect is usually kept secret.

"Unfortunately, there's no hard data," said the Rev. Marie M. Fortune of the United Church of Christ, who runs the center, which is based in Seattle.

While new disclosures on abuse cases involving Catholic priests are released almost daily, as the church comes under pressure from the press and prosecutors, it is not hard to find recent anecdotal examples of abuse in other groups as well.

In February, a North Dakota jury ordered a former Lutheran pastor, Dale Trautman, to pay $48,000 to a woman in his congregation with whom he had had a sexual relationship. The jury did not hold the national church liable. Also that month, a Maryland Episcopal priest, Kenneth Behrel, was found guilty of abusing a 14-year-old boy in the 1980's. In March, Howard Nevison, 61, the cantor at Temple Emanu-El in Manhattan, turned himself in to authorities on charges that he molested his young nephew.

Most major religious groups have guidelines on how to prevent and respond to accusations of pastoral sexual abuse. The policies differ not only by group but also within denominations, since oversight is often carried out regionally. Decentralized denominations like the Southern Baptist Convention and many fundamentalist Protestant churches have no national policy, leaving it to individual congregations.

"With a great many churches, there are no policies or procedures, even at the regional level," said Gary Schoener, a Minneapolis psychotherapist who has been consulted in more than 1,000 clerical sexual abuse cases. "And there's a huge and probably growing group of miscellaneous churches that aren't part of any kind of denomination where there's central authority."

In a legal case that got the attention of national religious groups in 1992, a Colorado jury awarded more than $1 million to a woman who had been molested by an Episcopal priest and held the local diocese liable for damages.

"That was the one that changed everything," Mr. Schoener said. "That was the first time a bishop in a diocese had been accountable in an adult case."

Joyce Seelen, the lawyer who represented the woman, estimated that she has handled 50 cases of clerical abuse in 20 years, covering Methodists, Episcopalians, the Church of Christ and the fundamentalist Church of the Nazarene.

"In my practice, I have not seen institutions taking steps to correct the problem," Ms. Seelen said. "Every one of the churches that we've been successful against walked into court and said, `We didn't know, and if we had known, we would have done something.' Over and over and over, what we saw was they didn't know because they didn't want to know."

The question of whether top church officials did too little to prevent abuse lies at the center of the civil lawsuit involving Mr. Thomas, the Lutheran pastor here.

"This guy should never have been allowed to be placed back into an environment where he could get at little kids," said Ed Hohn, a lawyer representing the plaintiffs.

According to court documents, in August 1996, while Mr. Thomas was a seminarian on a pastoral internship in rural Wilson, Tex., a sheriff's deputy concluded that he had given alcohol to two brothers, ages 10 and 12. The boys, who often slept at the pastor's house, also said they found a pornographic video. Ultimately, no charges were brought because the boys did not say that anything inappropriate had occurred.

Internal church documents confirm that a supervisory pastor, Mel Swoyer, investigated and filed a report. Mr. Thomas, the pastor wrote in a letter, is "an excellent intern" but "I still do not know what I think about Jerry's sexuality." The pastor also noted his concern that Mr. Thomas kept a bedside picture of a boy he had met at a church camp.

A year later, Mr. Thomas met suspicion during another pastoral internship, at a Lutheran church in Columbus. The church's pastor, Carol Stumme, told F.B.I. agents in 2001 that boys often went to Mr. Thomas's apartment. Though Mr. Thomas reassured her that nothing inappropriate was happening, she banned him from further church activities.

Mr. Thomas, who was ultimately ordained, arrived in Marshall in 1999 as the pastor of Good Shepherd Lutheran Church, next to a high school. Guidance counselors often recommended him as a mentor to troubled teenagers.

But in May 2001, federal and local investigators said they became suspicious after they learned Mr. Thomas was shopping for a truck for a 14-year-old boy. The boy later admitted he was blackmailing Mr. Thomas with a CD-ROM he had taken from the pastor. The CD-ROM contained video of teenage boys displaying their penises and, in one case, masturbating as an adult's voice can be heard encouraging him. There were also illegal child pornography videos on the CD-ROM.

Several boys told investigators that Mr. Thomas masturbated in front of one boy and that he showed them pornographic videos and let them drink alcohol. One boy, then 16, said in an interview with a reporter that Mr. Thomas had sexually assaulted him.

Mr. Thomas faces up to five years in prison after pleading guilty to the child pornography charge, but he has denied sexually assaulting the 16-year-old.

"He has pleaded guilty to what he's guilty of, and he adamantly denies any other charge," said Mr. Thomas's lawyer, Tonda Curry.

John Brooks, a spokesman for the Evangelical Lutheran Church in America, declined to comment on the civil suit against the church. He noted that Mr. Thomas had resigned as pastor before his arrest and that church officials had since removed him from their national clerical roster.

"We're pretty confident that after the facts are heard, the church will be exonerated," Mr. Brooks said.

He said that as a rule, the Lutheran church dismissed pastors found to have engaged in inappropriate behavior. "We respond to these things quickly," Mr. Brooks said. "We certainly do not move pastors who are not in compliance with our clerical standards. We do not move people from one church to another because of misconduct."

He said the national church had averaged "less than one case a year" involving pastors and child sexual abuse since it was founded 15 years ago. He estimated that the number of cases involving pastors and adults was three to five a year.

Jan Erickson-Pearson, a Lutheran pastor in suburban Denver, who previously worked as the national staff member assigned to clerical sexual abuse issues, said the church's efforts to prevent the problem were guided by a desire "to guard the integrity of the ministry and make sure that the church is a safe place."

Asked to explain the charges against Mr. Thomas, Ms. Erickson-Pearson responded: "This sounds like a flip answer, but why does this still happen? Sin."