Doe was abused during scouting trips and outings in eastern Oregon and in Nampa, Clark said.

Arnold was convicted of sexual abuse of a child under 16 in Bannock County in 1985, Clark said.

"We will prove that for at least five or six years after that he was still on the Boy Scout rolls, and we think still serving."

J. Craig Rowe, spokesman for the LDS Church in Idaho, said the church takes the allegations seriously. He criticized Clark's approach to the case.

"The Church of Jesus Christ of Latter-day Saints has a zero tolerance policy for child abuse and does all it can to help victims and report abuse. It will seriously investigate these decades' old allegations," Rowe said in a prepared statement.

"However, the way in which this case was filed raises a serious issue of which both the court and the public should be aware. The plaintiff's attorney contacted media before the lawsuit was even filed knowing the church could not respond, in an attempt to create headlines rather than discover the facts. This approach trivializes the seriousness of child abuse and its tragic consequences."

Clark said he has brought dozens of similar cases against the Roman Catholic church and is currently litigating seven cases against the LDS Church.

"Based on my experience I would expect to find a long, ugly, broken trail of child abuse," he said. "I'm conscious of where we are and I would say that these both are rightly respected institutions, but the fact is in the 1960s and 1970s they were not doing their job."