Some of the U.S. soldiers killed in a sneak attack at the governor's office in the Shiite holy city of Karbala last week may not have died on the scene and may have been briefly abducted before being killed, U.S. officials said Friday.

U.S. officials speaking on the condition of anonymity said the bodies of four of the five soldiers killed in the attack had been found as many as 20 miles away from the scene.

The brazen assault, 50 miles south of Baghdad on Jan. 20, was conducted by nine to 12 militants posing as an American security team. They traveled in black GMC Suburban vehicles — the type used by U.S. government convoys — had American weapons, wore new U.S. military combat fatigues and spoke English.

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.

The first U.S. military statement on the raid, which reported five soldiers killed and three wounded, said, "the PJCC is a coordination center where local Iraqi officials, Iraqi security forces and coalition forces stationed within the center meet to address the security needs of the population."

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.

A top Iraqi security official for Karbala province told the AP that the Iraqi guards at the checkpoint radioed ahead to their compatriots at the PJCC to alert them that the convoy was on its way.

Iraqi officials said the attackers' convoy divided upon arrival, with some vehicles parking at the back of the main building where the meeting was taking place, others parked in front.

The U.S. military in Baghdad received a first report of the attack about 6:15 p.m., the senior U.S. military officials said.

The attackers threw a grenade and opened fire with automatic rifles as they grabbed two soldiers inside the compound. Then the guerrilla assault team jumped on top of an armored U.S. Humvee and captured two more soldiers, the U.S. military officials said.

One U.S. soldier was killed in the melee at the compound, and three were wounded.

The attackers fled with the four and the computer and headed east toward Mahwil, in neighboring Babil province, about 25 miles away, the U.S. military officials said.

Iraqi officials said the U.S. military found the four U.S. soldiers in the Suburbans near Bu-Alwan, a village near Mahawil.

U.S. officials in Iraq, who had seen incident reports of the assault, said the documents indicated two of the soldiers were found in one of the Suburbans at one location and two others in a second Suburban elsewhere. The exact locations were not specified, they said.

Both sides agreed that — when found — three soldiers were dead and one was wounded and died as U.S. troops rushed the service member away for treatment.

Three days after the attack, the U.S. military in Baghdad announced the arrest of four suspects in the attack and said they had been detained on a tip from a Karbala resident. No further information was released about the suspects.

The Associated Press and FOX News' Nick Simeone contributed to this report.