A convicted child molester jailed in California may have committed sex crimes against thousands of victims, police said Thursday after finding computers, notebooks and meticulous, handwritten lists of boys' names and apparent codes for various sex acts.

San Jose Police Lt. Scott Cornfield described 63-year-old Dean Arthur Schwartzmiller (search) as "one of the most active child molesters we've ever seen."

During a search of his bedroom in San Jose (search), police discovered binders full of child porn and numerous logs with lists of more than 36,000 children's names — mostly boys — and codes that appear to indicate how he abused them.

"If one-tenth of these numbers are accurate, we're looking at hundreds of victims in a number of states. The reason we want to tell the world about this is because we believe he's been involved in child molestations in a number of countries," Cornfield said.

Schwartzmiller was being held without bail on one count of aggravated sexual assault on a child and six counts of lewd and lascivious conduct on a child, with each count alleging multiple victims. He was arrested in Washington state late last month and sent to San Jose on June 7.

A message left for his public defender was not immediately returned Thursday.

Authorities said Schwartzmiller apparently gained the trust of victims and parents by working as a home renovation contractor. San Jose police got involved after he allegedly befriended at least two boys in the city with gifts, invited them to his house for video games and movies, and molested them.

Schwartzmiller apparently did not register as a sex offender, so his history did not appear in the "Megan's Law" databases in California or other states, authorities said.

"It's as shocking to me as to you," said Sgt. Tom Sims, a supervisor with the department's child exploitation division. "I've never seen anything like this."

Although police said Schwartzmiller appears to have spent much of the past 30 years in California, he has been arrested on child molestation charges in New York, Arkansas and Washington. He also served prison time in Idaho for child molestation in the late 1970s, and is wanted in Oregon on sexual assault charges involving a minor.

In the 1980s, he lived in Brazil, and was extradited from there to Idaho again in the later part of the decade to serve more time, Cornfield said. Police believe he may have victims in Brazil and Mexico.

Authorities also arrested Schwartzmiller's roommate, another convicted child molester wanted for violating parole in Oregon. Fred Everts was charged with child molestation in San Jose.

In a separate case, Edilberto Datan, a 61-year-old San Diego man who has admitted to traveling to his native Philippines and having sex with eight underage boys, was sentenced Thursday to 17 years in federal prison and lifetime supervision.

The retired auditor for the California Department of Real Estate was arrested in 2004 at the airport in Los Angeles upon his return from the Philippines. Authorities said they found about 150 sexually explicit images of 18 teenage boys in his luggage and digital camera. Eight of the children were identified and located.