ISIS has claimed responsibility for the attack in Garland, Texas in what the terrorist group calls their first attack on U.S. soil, according to U.K.'s The Independent. The Monday night shooting, as HNGN reported, was at a contest for cartoon drawings of Prophet Mohammad.
The two gunmen have been identified as Elton Simpson and Nadir Soofi, roommates from Phoenix, Ariz. On Tuesday, a radio announcer on Islamic State radio based in Mosul, Iraq called Simpson and Soofi two of the group's "soldiers of the caliphate" and "brothers," according to The Independent.
"We tell America that what is coming will be even bigger and more bitter, and that you will see the soldiers of ISIS do terrible things," the broadcast said, according to The Independent.
Just before the attack, Simpson posted a Tweet with the hashtag #texasattack. Simpson wrote that he and his "bro" pledged allegiance to "Amirul Mu'mineen" ("leader of the faithful"). The term likely refers to ISIS leader Abu Bakr al Baghdadi, according to CNN.
The Twitter accounts have both been deactivated.
