William Toma adopted and then abused his stepdaughter, meticulously documenting pornographic photographs of the girl at 11, then at 12, then 13.

By then he had progressed to videotape and sent images of the girl to other countries, including Denmark where she appeared in a magazine for pedophiles.Toma is now in prison and the stepdaughter an adult. The pictures, however, continue to be reproduced again and again.

"The magazines are still out there today, and (the stepdaughter) is out there somewhere and continues to be victimized," said Ray Smith, U.S. Postal Service inspector and program manager.

The often silent world of pedophilia is much larger than the public may believe, Smith said Tuesday at the 11th annual Conference on Child Abuse and Domestic Violence at Weber State University.

The Postal Service is the nation's oldest federal law enforcement agency and has jurisdiction over criminal and civil matters that take place through the country's mail system. But a large portion of the investigations - 2,800 since 1984 - have been on child pornography.

This year, 40 percent of the pornographers either had a history of or were currently molesting children. Nearly all those consuming or producing the materials are men, usually white, and from middle or upper class backgrounds.

While the medium may have changed from the Scandinavian magazines of the '70s and '80s to the computer images of the '90s, the federal law has kept up, becoming more and more stringent in an effort to eradicate child pornography.

The nation didn't have a federal child pornography law until 20 years ago. Since then, the laws have come to prohibit computer downloading and uploading of images and the receipt and production of the pornography. Today, even possessing the materials is against the law.

But that doesn't mean it doesn't exist. Recently, Smith's office conducted Project Special Delivery and dismantled the largest child pornography business in U.S. history. More than 90 people have already been convicted. The pornography was made with boys as young as 7 in Mexico. The images were reproduced in a condo in San Diego and shipped across the country.

The kingpin of the operation - 47-year-old Troy Anthony Frank - had been convicted of molesting a child in Greeley, Colo., and fled to the Netherlands and then Mexico. He committed suicide shortly after authorities told him to turn himself in.

In Utah, the crimes are usually turned over to federal agencies because federal law is much more stringent than state law, said Salt Lake Police Sgt. Don Bell, who oversees the city's sex crimes division.

Just two weeks ago, a Salt Lake photo lab contacted police when a roll of film they were developing contained questionable nude pictures of a young girl.

Bell agreed the pictures were suspicious and turned the case over to law enforcement officials in Tooele, where the family lives. The case is still under investigation.

The crime is usually hard to detect, especially because of the prevalence of home computers and video technology, Bell said. About 18 months ago, police arrested a Salt Lake man after they found videos of him molesting his girlfriend's daughter. He is still in prison, Bell said.

The child abuse conference continues through Wednesday. More than 700 child protective investigators, medical personnel, court officials and parents from around the country are attending the annual event.