Garland shooting: Counter-terrorism officials probe online links with Isis of alleged Prophet Mohamed gunmen

Alleged gunmen posted messages on social media prior to Sunday's attack

Elton Simpson has been named as one of the two gunmen who attacked the Curtis Culwell Centre arena in Garland

Counter-terrorism officials are currently analysing the digital footprint of two men involved in the attack on the Prophet Muhamed drawing contest in Texas.

ISIS controls as many as 90,000 Twitter accounts to distribute propaganda and radicalise Westerners, according to the Brookings Institution, a Washington think thank.

On Tuesday, ISIS supporters claimed responsibility for Sunday’s attack at the Muhammad Art Exhibit and Cartoon Contest in Garland, Texas, allegedly carried out by two flatmates from Phoenix, Arizona.

Elton Simpson, 30, sent public messages on Twitter calling for violence from ISIS supporters alongside vowed enemies of Pamela Geller, the contest’s organiser. Nadir Hamid Soofi, 34, also tweeted links to Sunday’s event, and praised January’s Charlie Hebdo shootings in Paris.

While ISIS had not ordered the attack, officials have confirmed that the gunmen were apart of the terror group’s extended social network, the New York Times said.

Mr Simpson’s contacts included Somali American jihadist Mujahid Miski, a Minnesotan turned ISIS recruiter now overseas and Mohamed Abdullahi Hassan. Mr Hassan had suggested the Texas event as a possible target.

“The brothers from the Charlie Hebdo attack did their part,” Mr Hassan tweeted. “It’s time for brothers in the #US to do their part.”

Both Mr Simpson and Mr Soofi were wounded by a security guard before police shot and killed them. This is the first time ISIS has taken credit for an attack in the US and officials are searching for direct ties to the extremist group in Syria.

Nadir Soofi has been named as one of the two gunmen who attacked the event in Garland

“The ISIS guys are talking to these wannabes on Twitter all day long,” a senior law enforcement official told the newspaper. “It’s like the devil is sitting on their shoulder saying, ‘Come on, they’re insulting the prophet, what are you going to do about it?’ ”

The sheer number of online accounts declaring allegiance to ISIS and messaging threats may give intelligence officials a hard time deciding on what is, and what isn’t a legitimate threat. ISIS accounts have already threatened similar attacks across the states.

Will McCants, head of the Brookings Institution’s Project on US Relations with the Islamic World, said jihadists have become to favour shootings over bombings — they’re simpler but will still attract global news coverage.

“This is exactly the tactic ISIS has been encouraging in the West,” Mr McCants told the Washington Post.

“It’s much easier to do, and you don’t risk being discovered. If you’re trying to build a bomb, you have to get materials, and it exposes you to arrest. A shooting spree — it’s hard to detect - shooting sprees draw international media attention. After a long love affair with the bomb, they have moved to shooting sprees."