One police source told Reuters that the 10-year-old nephew of chief judge Mohammed al-Ureybi and a third person in the car were wounded in the attack yesterday. A second source said the nephew had died and the third person, who was Ureybi's sister, was seriously wounded.
It was not immediately clear if the attack was linked to Ureybi's work at the Iraqi High Tribunal. He was appointed chief judge only last week after the government sacked his predecessor for telling Saddam the former president was "not a dictator".
Three defence lawyers working for Saddam and his co-accused have been killed over the past year and international legal rights groups have questioned whether he can have a fair trial in a country on the brink of sectarian civil war.
The first police source identified the dead man as Kadhem Abdul Hussein, who was in his 40s, and named his son as Karrar. The boy was Ureybi's nephew and the dead man was the husband of the judge's sister, he said.
Ureybi is from the majority Shi'ite community now dominant in Iraq after years of oppression under Saddam's mostly Sunni rule. He has taken a firm line with the accused in the month-old trial for genocide against the Kurds and has ejected Saddam from court in each of the three sessions over which he has presided.
Tribunal judges, like leading Iraqi politicians, live under tight security. Militants have frequently targeted the relatives of prominent figures, seeking easier targets because the family members enjoy considerably less - if any - protection.