"Over the past several days, Coalition forces in Basra and Hillah captured Qais Khazali, his brother Laith Khazali, and several other members of the Khazali network, an organization directly connected to the kidnapping and murder in January of five American soldiers in Karbala," the military said in a statement today.

Qais Khazali has been a spokesperson for Moqtada al-Sadr, and is commonly referred to as his senior aide.

Khazali is accused of involvement in the brazen attack on the Karbala Provincial Joint Coordination Center in late January. In that operation, two-dozen gunmen in U.S. military uniforms arrived in seven GMC SUVs with tinted windows, similar to those used by top U.S. military officials and security contractors, killed five U.S. soldiers, but spared Iraqis, according to US sources at the time.

US officials have also said the brothers are suspected of being involved in a network that employs EFPs.