LOS ANGELES — A Los Angeles judge has ruled that a film producer facing federal obscenity charges could be retried even though his first trial ended prematurely after the judge, Alex Kozinski, presiding judge of the 9th U.S. Circuit Court of Appeals, stepped down amid revelations of possessing a Web site with sexually explicit photos.

The trial against Ira Isaacs, the defendant, began on June 11. Later that day, an online article in the Los Angeles Times revealed the existence of Kozinski’s Web site, which had photos depicting naked women painted like cows and a man cavorting with a sexually aroused farm animal.

Two days later, Kozinski, who was serving as a trial judge in the case, filed an order for recusal, and the case ended in a mistrial.

Isaacs had argued that the indictment against him be dismissed on double jeopardy grounds. “Clearly there was no basis for Judge Kozinski to disqualify himself,” Isaacs wrote in his motion. “He did nothing wrong and should have proceeded with the case.”

In a ruling made available on Monday, U.S. District Judge George King, who was assigned to the case following Kozinski’s recusal, disagreed.

“In this case, Judge Kozinski’s recusal, which we find proper, is a significant factor in our determination of whether he exercised sound discretion in concluding that manifest necessity for mistrial existed,” he wrote.

As an aside, the judge disagreed with prosecutors that Isaacs had consented to the mistrial.

An attorney for Isaacs, Roger Jon Diamond, of Roger Jon Diamond Law Offices in Santa Monica, Calif., said he planned to appeal the ruling to the 9th Circuit.

“We’re disappointed that Judge King found the recusal was proper,” he said. “We think this case has widespread significance, and we’re concerned about Judge Kozinski’s future participation in First Amendment cases on the 9th Circuit because if this decision stands we’re concerned that Judge Kozinski would disqualify himself in all First Amendment cases.”