Police throughout Iraq look for clues after multiple car bombings kill or injure dozens.<br /> <br />In Basra, police say two car bombs exploded simultaneously, wounding at least 17.<br /> <br />One local shop owner saw both blasts go off.<br /> <br />(SOUNDBITE) (Arabic) OWNER OF SHOP AT BLAST SCENE, KADHIM FALEH, SAYING:<br /> <br />"A blast took place here and one minute later a second car bomb went off here. A man was wounded here [points] and another one there and a third one was lying under tires."<br /> <br />The attack was part of a wave of car bomb attacks that ripped through busy streets and markets in mostly Shi'ite provinces.<br /> <br />The deadliest attack took place in Hilla, south of Baghdad, where two more car bombs blew up in quick succession, killing at least five people and injuring many more.<br /> <br />It is not immediately clear who is behind the attacks, which appear to have been coordinated.<br /> <br />Sunni Islamists and other insurgents, including al-Qaeda, have been regaining ground this year.<br /> <br />So
