Alex Kozinski, chief judge of the 9th U.S. Circuit Court of Appeals, asked an ethics panel of the court to initiate proceedings after the disclosure about his trove of sexually explicit material.
"I will cooperate fully in any investigation," Kozinski said in a statement.
Kozinski, 57, left court Wednesday without comment after suspending the trial of Ira Isaacs, who is charged with obscenity for selling movies depicting bestiality and fetishes involving feces and urination. The delay until Monday will give lawyers time to consider whether to ask for Kozinski to step down from the case.
The Los Angeles Times reported Wednesday that Kozinski had posted sexual material on his personal Web site and then blocked access after being interviewed about it Tuesday evening. He told the Times he was responsible for posting at least some of the images and videos.
The computerized cache included a picture of two nude women on all fours painted to look like Holstein dairy cows, images of masturbation, a video of a man being pursued by a sexually aroused donkey and a slide show featuring a striptease with a transsexual.
"If you found this kind of thing in your kid's bedroom you would wash your kid's mouth out with soap. We expect more from a judge," said Laurie Levenson, a former federal prosecutor and law professor at Loyola University Law School. "Character counts for judges because they have so much power and affect so many people's lives."
Kozinski who has been mentioned as a possible Supreme Court candidate, is known for his intellectual rigor, writing flourishes and an outlandish - some say boorish - personality.
But the graphic material has opened questions about his fitness to serve on the high-profile obscenity case as well as the standard for what types of images are taboo, particularly on a judge's personal Web site.
Although he requested an investigation, it's unclear what, if any, discipline Kozinski could face. Circuit judges are appointed for life and can be fired only by Congress, though fellow jurists can censure them.
Kozinski did not immediately respond to a request for an interview Thursday.
The judge, a married father of three sons, claims to build his own computers but told the Los Angeles Times he didn't know the Web site was accessible to Internet surfers. One of his sons, Yale Kozinski, later told The New York Times that the site is registered to him and he maintains it, but neither father nor son made clear who posted the images in question.
Federal rules say judges should "act at all times in a manner that promotes public confidence in the integrity and impartiality of the judiciary." But does material on a judge's personal Web site cross that line?
"Even if it is private, the problem for him is the cat is out of the bag," said Tom Fitton, president of conservative Judicial Watch. "You're going to have questions about his impartiality."
But Erwin Chemerinsky, dean of the law school at University of California, Irvine, said the material would not permanently harm Kozinski's reputation.
"It's much ado about very little," Chemerinsky said. "There is no indication that this material is even close to obscenity."
Cyrus Sanai, a Beverly Hills lawyer who has had a long-running dispute with the 9th Circuit, took credit for bringing the graphic material to light.
Sanai said he discovered the sexual content in December while monitoring the judge's Web site as part of his legal rift with the court. After downloading the files, Sanai said he began contacting reporters at various publications in January to bring attention to what he called widespread ethical problems on the 9th Circuit.
He provided a copy of the files to The Associated Press on Wednesday, which appeared to mirror the Times' descriptions of videos and pictures on the Web site.