In a saga with all the elements of a Hollywood thriller, an appeals court judge who is one of America’s leading legal intellectuals stands accused of maintaining a public stash of online fetish pornography just as he has begun overseeing a criminal trial involving the distribution of sexually explicit scatological videos.

Opening arguments were getting under way in the obscenity case in federal court in Los Angeles yesterday morning when the Los Angeles Times posted a story online reporting that Judge Alex Kozinski’s Web site contained images including “naked women on all fours painted to look like cows and a video of a half-dressed man cavorting with a sexually-aroused farm animal.” The site also contained pictures of urination and defecation, though they were “not presented in a sexual context,” the paper said.

Judge Kozinski, 57, disabled the site after being asked about the images in an interview Tuesday night. He said he was not aware the images and videos could be publicly accessed. He called some images “degrading … and just gross,” but defended other items as “funny.”

“I think it’s odd and interesting. It’s part of life,” Judge Kozinski told the Times.

The disclosure led to the suspension yesterday of the trial of a producer of so-called scat porn, Ira Isaacs, the Associated Press reported last night. At an afternoon session in Pasadena, Judge Kozinski brought up the press report about his Web site and said both sides were welcome to file motions to recuse him from the case. Ms. Isaacs’s attorney, Roger Diamond, said he opposed a recusal, while the prosecutor had no immediate position, the wire service said.

The Pasadena session was arranged so jurors could watch the videos at issue. “Four-and-a-half hours of very disgusting porn movies, scatological, feces, urine, animals, bestiality, the works,” Mr. Diamond told The New York Sun at midday yesterday.

A leading expert in legal ethics, Stephen Gillers of New York University, said the judge would be wise to withdraw from the trial. “He has to get off that,” the professor said. “Stepping aside now at least shows some sensitivity to the public’s perception, and refusing to step aside does the opposite.”

However, several lawyers said declaring a mistrial over a defense objection could raise a double jeopardy issue that might prevent Mr. Isaacs from being retried. In a possible reference to that complication, the judge reportedly told the lawyers yesterday: “I’m very sorry I didn’t know about this before the jury was sworn.”

Judge Kozinski is known for his libertarian leanings and has won acclaim for his contrarian and often irreverent opinions. “The parties are advised to chill,” he wrote in a 2002 trademark dispute involving a musical reference to Barbie dolls. He once posted online a video of his own appearance decades ago on “The Dating Game.”

“He’s a wonderful judge, a brilliant mind,” Mr. Gillers said. “He routinely sends his clerks to the Supreme Court of the United States. He’s got an international reputation that is well deserved.”

Asked about the impact of the disclosure, the professor said, “It’s a tragedy, what can you say? … At best, he’ll have to deal with a lot of humiliation, but he can come back from it.”

Legal analysts said the judge was never seriously considered for the Supreme Court, and probably would never be, because of his unpredictable opinions. Mr. Gillers said the judge could be disciplined by his colleagues, but could only be removed by impeachment, which the professor said would be unwarranted.

Several years ago, the judge mounted an aggressive public campaign against filtering of court computers to block pornography and file sharing. He was nearly censured by his colleagues for entering a server room and physically shutting down the filters, California Lawyer magazine reported.

The judge told the Times that he did not use court computers to work on his site. The newspaper did not say how it learned of the story, but Mr. Diamond told the Sun that the report was triggered by a Beverly Hills, Calif., attorney who has clashed with Judge Kozinski, Cyrus Sanai.

In an interview last night, Mr. Sanai confirmed that he told the Times about the judge’s Web files. “The stuff isn’t all-American Jenna Jameson, Ron Jeremy pornography. It’s all really weird stuff,” Mr. Sanai said. He said, however, that he was troubled only by the judge’s posting of copyrighted songs, something college students and others are regularly sued over.

The judge’s trouble with Mr. Sanai began in 2005, when the attorney wrote an article with examples of 9th Circuit judges allegedly ignoring circuit precedents. Judge Kozinski wrote a rebuttal that noted Mr. Sanai’s personal stake in one of the disputed issues. The attorney, who had a motion pending in that case, filed a complaint alleging that the judge broke rules barring judges from commenting or lobbying on pending cases. The complaint was dismissed, but Mr. Sanai refiled it after the judge re-posted the article on the same site with the explicit photos.

The judge did not respond to a request for comment placed through a 9th Circuit spokesman. However, in a statement posted yesterday on a legal gossip site, Judge Kozinski said one of his sons “uploaded a bunch” of the files in question. “I sure don’t remember putting some of that stuff there,” the judge wrote to Abovethelaw.com.

Adding more drama to the day, Judge Kozinski abruptly recessed the morning session of the trial yesterday to gather information on the illness of one of his appeals court colleagues, Judge Stephen Reinhardt. The judge’s flight to Washington yesterday was diverted to Las Vegas after he had trouble breathing. He was admitted to a hospital there for tests.

Both men were scheduled to take part in a panel discussion in the capital on Saturday about sexual orientation and religious liberty.