The criminal prosecution of a hard-core pornographer turned into a personal trial for the presiding judge, who called for an investigation Thursday into his own conduct for storing lewd photos and videos on a publicly accessible Web site.

Judge Alex Kozinski asked an ethics panel of the 9th U.S. Circuit Court of Appeals to initiate proceedings after the disclosure about his trove of sexually explicit material.

"I will cooperate fully in any investigation," Kozinski, chief judge of the circuit, said in a statement.

Kozinski, 57, 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.

"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."

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.

Although he requested an investigation, it's unclear what, if any, discipline Kozinski could face. Circuit judges are appointed for life and can only be fired by Congress, though they can be censured by fellow jurists.

Kozinski did not immediately respond to a request for an interview Thursday.

He 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 existence of the videos and pictures was first revealed by the Los Angeles Times, which reported that Kozinski had acknowledged the material on his personal Web site, but blocked access to it after being interviewed. He claimed the images were not obscene.

The judge, a married father of three sons, claims to build his own computers but told the newspaper 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.