It is the first time the Islamic State has claimed responsibility for an attack on U.S. territory. After Sunday’s shooting in Texas, in which two gunmen opened fire outside a controversial cartoon contest depicting Prophet Muhammad. An announcer from the ISIS radio station referred to slain suspects Elton Simpson and Nadir Soofi as two of the terror group's brothers and soldiers of the caliphate. But it is not clear whether the extremist group had a direct connection to the pair, or was merely being opportunistic and using the attack in Garland as propaganda. The duo managed to wound an unarmed school security officer before they were killed by a lone security guard.