Soon after he was arrested in Everett in 2005, Dean A. Schwartzmiller was labeled one of the most prolific child molesters in the country, with an estimated 250 victims scattered over 35 years and eight Western states.

On Thursday, attorneys added a new allegation to Schwartzmiller's history: pedophile Scoutmaster.

A 46-year-old man from Eastern Washington, who filed a lawsuit in King County this week, has accused Schwartzmiller, 70, of being a predatory assistant Scoutmaster in Spokane in the late 1970s. The victim identified by the initials M.D., accused other troop leaders of encouraging Scouts to engage in "sexual activities" during a camp out.

Schwartzmiller, according to police, kept a 456-page log of his alleged victims, with categories for "blond boys" or "boys who just cried." He has at least seven sex-crimes victims and a 2006 conviction for which he is serving 152 years in prison in California.

But this allegation is the first involving the Boy Scouts. At the time Schwartzmiller volunteered in the Spokane Scout troop, he'd already been convicted twice of abusing boys in Alaska and Idaho, and had a third charge pending.

"This is someone who clearly had a history. The Boy Scouts should have done a due-diligence investigation," said James Rogers, M.D.'s attorney in Seattle.

Deron Smith, a Texas-based spokesman for the Boy Scouts of America, said the organization now institutes mandatory background checks and bans one-on-one contacts. Neither policy was in place at the time of the allegation.

"There is no abuse more abhorrent and intolerable than that of children — particularly to the Boy Scouts of America for which youth protection has always been a key priority — and all victims and their families deserve our deepest sympathies," he said in statement.

The Boy Scouts of America, the largest youth-serving organization in the nation, has been battered with sexual-abuse allegations as its cache of confidential records of abuse allegations — dubbed the "red-flag files" — has come to light.

A Seattle attorney, Tim Kosnoff, and a Portland attorney, Kelly Clark, have both gained access to the files through litigation. In 2010, Clark, who is co-counsel on the Schwartzmiller lawsuit, won a $20 million jury verdict and access to 1,247 files.

Kosnoff said Schwartzmiller's name does not appear in the files, which were records of complaints against Scout leaders. The files show complaints of at least 52 Scoutmasters in Washington from 1971 to 1990, including a Yakima man who served time in a sexual-deviancy-treatment program before volunteering for Scouting.

Schwartzmiller, a plasterer by trade, often fled when facing charges and was once picked up in Brazil. When convicted, he was an adept jailhouse lawyer, twice winning acquittal on appeal.

In 2005, he was arrested hiding in the bushes outside the Everett home of a longtime friend after fleeing California during a child-abuse investigation. During trial for molesting two boys, Schwartzmiller acted as his own attorney, questioning his victims.

He is appealing his conviction and claims his extraordinary log of victims was fiction.

Rogers said he suspects there are other victims from Schwartzmiller's Scouting days. "Even as we sit here today, we don't know how far back this goes," he said.

Jonathan Martin: 206-464-2605 or jmartin@seattletimes.com. On Twitter @jmartin206.