The chief judge of the federal appeals court in San Francisco, whose pornography-laden Web site hit the headlines while he was presiding over an obscenity trial in Los Angeles, invited an investigation Thursday by a judicial disciplinary agency.

Judge Alex Kozinski said in a statement that he has asked the Ninth U.S. Circuit Court of Appeals' Judicial Council to begin proceedings to determine whether he engaged in misconduct. The council has the power to censure a judge, temporarily halt case assignments, or take the first steps that could lead to congressional impeachment and removal from office.

"I will cooperate fully in any investigation," Kozinski said.

The council, made up of appeals court and trial judges, normally handles complaints against any federal judge in the nine-state circuit. But because Kozinski is the council's chairman, he invoked a rule that allows Chief Justice John Roberts of the U.S. Supreme Court to reassign the case to a Judicial Council in one of the other 11 federal circuits.

On Wednesday, Kozinski halted the obscenity trial of Ira Isaacs until Monday to give Justice Department prosecutors time to decide whether to seek his removal from the case. Isaacs is charged with distributing sexual fetish videos that violate obscenity laws.

Earlier Wednesday, the Los Angeles Times disclosed some of the contents of the now-disabled Web site, http://alexkozinski.com. They included images of bestiality, masturbation, a slide-show striptease and two naked women on all fours painted as cows.

Kozinski said Wednesday that the site was maintained by one of his sons and was used by family members to store various photos and documents. While not denying responsibility for the Web site, he said he wasn't sure whether he had intentionally stored any of the sexually explicit images, and said they might have been sent by others or uploaded by accident.

He said he had believed it was a private site that others could see only with his permission, until he learned otherwise this week from the newspaper and his son.

"I don't pay much attention to what's on there," Kozinski told The Chronicle. "There's lots of stuff I see (on the site) and I don't remember. I haven't gone through and looked at it. Some of it, I should have. ... I had no intention of making these files public."

Beverly Hills lawyer Cyrus Sanai, who exchanged attacks with Kozinski in 2005 in dueling columns in a legal newspaper about court procedures and precedents, said in online postings Wednesday that he downloaded the images from Kozinski's Web site in December and had provided them to the Times and other publications.

Kozinski's "efforts to have his son take the rap are far more contemptible than any of the porn he put up," Sanai said in a message to the legal blog Patterico's Pontifications.

Kozinski, 57, was appointed to the court by President Ronald Reagan in 1985 and began a seven-year term as chief judge in December by virtue of seniority. Known as a libertarian on free-speech issues, he led the successful opposition to a proposal by national court administrators in 2001 to monitor Internet use by federal court employees, including judges.

As a Judicial Council member, he argued in a dissenting opinion in 2005 that a Los Angeles federal judge should have been disciplined for allegedly showing favoritism to a litigant. Since becoming chief judge, Kozinski has directed the court to post disciplinary orders against lawyers and judges online.