FOX News's take:
http://www.foxnews.com/story/0,2933,247180,00.html
The raid, as explained by Iraqi and American officials, began after nightfall at about 6 p.m. on Jan. 20, while American military officers were meeting with their Iraqi counterparts on the main floor of the Provisional Joint Coordination Center (PJCC) in Karbala.
and
Iraqi officials said the approaching convoy of black GMC Suburbans was waved through an Iraqi checkpoint at the edge of Karbala. The Iraqi soldiers believed it to be American because of the type of vehicles, the distinctive camouflage American uniforms and the fact that they spoke English. One Iraqi official said the leader of the assault team was blond, but no other official confirmed that.
So, who owned the suburbans?