Updated

BAGHDAD-- Iraqi police Friday hunted for the killer of a Shiite who was responsible for purging loyalists of deposed ruler Saddam Hussein. The official was once implicated in a bombing that killed Americans.

Scores of people took part in the funeral procession Friday morning for Ali al-Lami, who was often accused of working with neighboring Shiite Iran to sideline Sunnis from power and re-ignite sectarian tensions. He headed a committee tasked with rooting out those with ties to Saddam Hussein and barring them from important government jobs.

He was fatally shot by gunmen while driving his car late Thursday -- the latest victim of an assassination campaign across Iraq that has killed tens of political and governmental figures. Supporters said he did not travel with armed guards, a rarity for Iraqi government officials, who usually live in heavily armed compounds and travel in multi-vehicle convoys with armed escorts.

His casket, wrapped in the Iraqi flag, was carried by weeping relatives and friends from his neighborhood in Baghdad's eastern district of Sadr City. He was to be buried in the holy Shiite city of Najaf in the south.

Mourners praised his work to bar former members of Hussein's Baath Party from government posts, a role that fueled charges last year that Iraqi Shiites, backed by Iran, were trying to keep hundreds of Sunni candidates from running in the parliamentary election.

"He's a hero," said Abu Ali, a traditional nickname that means father of Ali, who was among the mourners. "This person cheered the Iraqis' hearts...a star just fell," he added. He did not give his full name.

It was not immediately clear who killed him. Security forces said an investigation was under way. Supporters and close friends of al-Lami accused the Baath Party loyalists of killing him, although the Shiite community has also been beset in the past by rivalries that often play out with violence on the streets.

"The first suspect are the Baath Party members who are angry at his campaign against them," said Ali Mahmoud, a member of the Accountability and Justice Committees.

"His assassination will make us stronger than before in chasing down Baathists and Saddamists to keep them out of all government levels," Mahmoud pledged.

Al-Lami was arrested by U.S. and Iraqi forces in 2008 for suspected ties to Iranian-backed Shiite militias, and was accused by U.S. officials at the time of being involved in a bombing that killed eight people, including two American soldiers and two State Department employees.

His arrest reinforced suspicions about Tehran's influence within the Shiite-led Iraqi government. Al-Lami denied the charges.