“The government has a pretty high burden,” he said. “They have to be able to show that someone knowingly recruited, enticed, harbored and patronized a person and then gained value from it.” He said he was “not convinced the government has a case,” adding, “Was the line crossed from content production to sex trafficking?”

In court filings, Mr. Pratt and Mr. Wolfe, who own the websites GirlsDoPorn and GirlsDoToys, said the women had signed contracts that stated the videos they appeared in could be “used anywhere, anyhow, for any purpose.”

The women also recorded videotaped statements stating that they consented to the videos being used in any way and were not under the influence of drugs or mind-altering substances, according to civil filings from the defendants.

Mary Anne Franks, a law professor at the University of Miami who is the president of the Cyber Civil Rights Initiative, said many women in the pornography industry have lodged similar complaints of coercion but have not felt comfortable telling anyone. Or, she said, they were afraid that complaints would lead to their not working again.

“There’s just a massive amount of fraud and coercion,” said Ms. Franks, who co-produced a documentary about the world of amateur pornography. “It’s a very welcome development that all porn companies will be put on notice that there is an appetite to investigate these cases.”

Significant criminal charges have not been brought by federal authorities against pornography producers for more than a decade. In 2008, Paul F. Little was sentenced to 46 months in jail after being convicted on multiple obscenity charges.

Last year, a federal law strengthened the policing of sex trafficking online.

Southern California, especially the San Fernando Valley, has historically been home to major pornography studios and producers, but the internet has made it possible for anyone with a cellphone camera to produce and upload explicit content. And the internet involves interstate commerce, which is regulated by the federal authorities.