On Saturday, police found the bodies of Ahmed Midhat al-Mahmoud, 22, a lawyer, and two of his bodyguards in northern Baghdad's Azamiyah district, said Busho Ibrahim Ali, Iraq's deputy justice minister.
The killings came five months after the judge, Midhat al-Mahmoud, survived a December 4 suicide bomb attack against his home.
Al-Mahmoud leads the Supreme Judicial Council, a judicial supervisory body that, among other things, swears in all judges and parliament.
The al-Mahmoud family is Shia, and the three bodies were found dumped on a street in the mostly Sunni Arab neighbourhood of Azamiyah.
Elsewhere, five Iraqis were killed in drive-by shootings on Saturday, including a tribal sheikh, while a US Army soldier died in a roadside bomb attack, officials said.
A woman weeps as a minibus
carries a coffin of a relative
The bodies of three Iraqis who had been kidnapped and tortured also were found in the capital, police said.
In Mosul, suspected insurgents riding in what looked like a taxi shot and killed Idrees Shihatha, a local tribal sheikh, as he drove his car, said police Brigadier Abdul-Hamid al-Jibouri.
In another part of Mosul, a drive-by shooting killed four Iraqis and wounded one who were driving to the city from another part of Iraq, said al-Jibouri.
Eight Iraqis died in other violence on Friday.
The bullet-riddled bodies of four Shia were found dumped near Baqouba, 60km (35 miles) northeast of Baghdad. Two gun battles that day killed police Lieutenant Oras Habib in Baghdad and a local official of the Patriotic Union of Kurdistan party in Kirkuk, 290km (180 miles) north of Baghdad, police said.
Prime Minister-designate al-Maliki
has until May 22 to form a cabinet
The violence came as Nouri al-Maliki, the prime minister-designate, is struggling to put together his new cabinet, the final step in establishing his government of national unity.
The pace has been slow because of competing rivalries among political parties, most of which represent religious or ethnic groups.
Frustration with the process led one Shia party, Fadhila (Virtue), to announce on Friday that it was withdrawing from the cabinet negotiations, saying the process was being driven by partisan self-interest and US pressure.
The party said its 15 legislators will form an opposition bloc in parliament.
Al-Maliki is working against a constitutional deadline of May 22 to present his cabinet to parliament for approval. Squabbles over top posts such as the oil, defence and interior ministries threaten to push the talks down to the wire.
Some legislators have suggested that al-Maliki could present some of his cabinet on Sunday and take over the defence and interior ministries until all parties agreed on choices to lead them. The defence ministry controls the military, and the interior ministry oversees police.
The death of the US soldier from the Army's Multinational Division-Baghdad at 4 am raised to 2,437 the number of members of the American military who have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.