An Army maintenance unit that lost eight soldiers and had several taken prisoner in Iraq was sent in the wrong direction by other American soldiers as they sped to catch up to their convoy, a Texas congressman said Friday.

The 507th Maintenance Co. (search) was directed to go east at an American checkpoint and had traveled several miles in the outskirts of Nasiriyah when their commander realized they were heading in the wrong direction, said Rep. Silvestre Reyes.

Reyes is a Democrat from El Paso, home to Fort Bliss (search), where the 507th is based. He was briefed Friday by the Defense Department (search), which has been investigating the ambush.

The 507th members were doubling back when they were attacked with small weapons fire. Iraqi trucks armed with machine guns also began following them and blocked their retreat with their large trucks and other obstacles, Reyes said.

Reyes said the attack was more of a "rolling ambush" because the 507th vehicles were moving at high speed as they doubled back.

Several members of the company were captured during the March 23 ambush and the bodies of eight others were found when Marines rescued one of the captured, Pfc. Jessica Lynch.

Reyes said the Defense Department does not know whether the American soldiers manning the checkpoint belonged to the Army or Marines. He said that remains under investigation.