Islamic State (ISIS) has claimed official responsibility for Sunday's shooting attack in a Dallas suburb on Sunday, calling the two gunmen "soldiers of the caliphate," according to BBC.
On Sunday night, two armed terrorists opened fire on a security officer outside of a contest for cartoons depictions of the founder of Islam, Mohammed, in a suburb of Dallas, Texas. The American Freedom Defense Initiative was hosting a contest that would award $10,000 for the best cartoon depicting the Prophet.
Local police shot both terrorists dead at the scene; one was later revealed to have tweeted allegiance to ISIS.
But on Tuesday, an official announcement was broadcast on the terror group's al-Bayan Radio news bulletin, which further claimed that the exhibit "was portraying negative pictures of the Prophet Muhammad."
"We tell America that what is coming will be even bigger and more bitter, and that you will see the soldiers of the Islamic State do terrible things," the statement released by the group said.
The gunmen were identified late Monday as Elton Simpson, 30, and Nadir Soofi, 34, according to the Washington Post. The two men were roommates; Simpson had previously been suspected of attempting traveling abroad to wage jihad, or Islamic holy war.
Court documents revealed that Simpson had been under government surveillance since 2006 and was charged with lying to federal agents about his intentions to travel to Somalia in 2010.
He was convicted in an Arizona court for lying, but not for terrorism, according to BBC. The judge stated in the ruling that insufficient evidence had been brought for terrorism charges; Simpson was fined and sentenced to three years' probation.