Sunni militants are suspected of being responsible for the attack late on April 28 at a roadblock in a busy commercial area near the shrines of Imam Hussein and his half-brother, Abbas, both major Shi'ite holy sites.
No damage was reported to the shrines, which are some of the best protected sites in Iraq because of their holy status.
An Associated Press report says that after the blast, angry crowds threw stones at police, accusing authorities of failing to protect them.
It was the second deadly car bombing in the area this month, following an April 14 attack that killed more than 40 people.
(compiled from agency reports)