The Brigades of Martyr Ahmed Yassin was a previously unknown group that claimed responsibility for the killing of four U.S. security contractors in Fallujah, Iraq. <P><br /><br />In March 2004, masked men ambushed a convoy of security contractors from the firm Blackwater Security Consulting as they drove through the restive streets of Fallujah, a hotbed of Iraqi resistance.  The assailants raked the convoy with gunfire and threw grenades in to the vehicles, killing four of the six passengers.  After the attack, the bodies of some of the victims were dragged through the streets by a mob, mutilated, and hung from a bridge.  <P><br /><br /><br />Shortly after the killings, the Brigades of Martyr Ahmed Yassin claimed responsibility for the attack.  The group said it was in response to the killing of Sheik Ahmed Yassin several days earlier by the Israeli military.  Yassin was the spiritual leader of HAMAS, a Palestinian group responsible for hundreds of terrorist attacks.  In a statement of claim, the group remarked that the killings were "a gift from the people of Fallujah to the people of Palestine and the family of Sheikh Ahmed Yassin who was assassinated by the criminal Zionists."  The group also called for an end to the U.S. occupation of Iraq, but did not elucidate a specific ideology beyond these statements. <P><br /><br /><br />While the ambush of the contractors was well-planned, it is unlikely that the Brigades of Martyr Ahmed Yassin had been established before this incident.  The ambush was just one in a series of attacks by multiple perpetrators on U.S. military and affiliated targets in Fallujah. It is possible that the Brigades took the opportunity to claim this incident as a way of venting anger over Yassin's death, and the actual perpetrators of this attack may not have been responsible for the public statements of claim.  While it can't be proven that the Brigades of Martyr Ahmed Yassin was not actually an established organization, the group has not been responsible for further attacks, and has not released any other public statements.<br />