U.S. intelligence agencies investigating the kidnapping of three Americans in Baghdad, Iraq last week are focusing their probe on three militant Islamic groups closely affiliated with Iran. Asaib Ahl al-Haq, Kata'ib Hezbollah and the Badr Organization are Shi'ite militia groups that are part of Iraq's Popular Mobilization Front, a group closely tied to Iran, according to the Counter Extremism Project, a New York-based advocacy group.