Baghdad, Iraq ? A judge on the special tribunal that will put Saddam Hussein and members of his former regime on trial was assassinated Tuesday in the Iraqi capital, according to an Iraqi police official and a media report.

Judge Barwez Mohammed Mahmoud and a relative were killed in northern Baghdad’s Azamyiah district, the official told The Associated Press early today on condition of anonymity.

Al-Arabiya, the Dubai-based satellite TV news network, reported that the judge and his son died in the attack. The network said the men were killed near their house in northern Baghdad. The New York Times reported that the son, Aryan Mahmoud, was a lawyer with the tribunal.

The assassination came as thousands of mostly black-clad Iraqis protested outside a medical clinic in Hillah, a city 60 miles south of the capital where a suicide car bomber killed 125 people a day earlier.

The protesters, braving the threat of another attack as they waved clenched fists, condemned foreign fighters and chanted “No to terrorism!”

Police prevented people from parking cars in front of the clinic or the hospital, where authorities blocked hospital gates with barbed wire to stave off hundreds of victims’ relatives desperate for information on loved ones.

The judges on the special tribunal have not even been identified in public because of concerns for safety, but Mahmoud was apparently the first one to die in Iraq’s insurgency. Officials with the Iraqi government and the Iraqi special tribunal couldn’t be reached before dawn today for comment.

The killings came just one day after five former members of Saddam Hussein’s regime — including one of his half brothers — were referred to trial for crimes against humanity.

The announcement Monday by the tribunal marked the first time that the special court issued referrals, similar to indictments, which are the final step before trials can start.