An online ISIL persona run by internet troll Joshua Ryne Goldberg had posted maps to the exhibition, and urged his followers to attack the event.

[28] Prior to the attack, ISIL had urged followers and sympathizers who were unable to join the fighting in the Syrian Civil War to carry out jihad in their home countries.

[9][30] Approximately three hours prior to the start of the contest, the FBI had alerted the Garland Police Department that a suspected extremist, identified as gunman Elton Simpson, was "interested in the event" and could show up there.

[1][34] The "First Annual Muhammad Art Exhibit and Contest" event was hosted at the Curtis Culwell Center, rented from the Garland Independent School District.

In his tweet, he said he and an accomplice had pledged allegiance to "Amirul Mu'mineen", which Paul Cruickshank of CNN said probably referred to ISIL leader Abu Bakr al-Baghdadi.

[39] Just before the event was set to end at around 7:00 p.m.,[28] two men wearing body armor and equipped with three rifles, three handguns, and 1,500 rounds of ammunition[1][40] drove up to a police car that was parked next to a barricade erected in front of the center.

[5][44] He was treated at a local hospital and confirmed to be released at 9:00 p.m.[45][46] Authorities were worried that the suspects' car could contain an incendiary device; as a precaution, several nearby businesses were evacuated.

[55][57] Simpson was a longtime worshiper at the Islamic Community Center of Phoenix, starting in approximately 2005, but according to the mosque's president, Usama Shami,[58] he stopped showing up months prior to the attack.

[67] Simpson was found guilty of making a false statement regarding international and domestic terrorism, and was sentenced to three years probation and a $600 fine in August 2011 after lying to a federal agent about his travel plans.

His lenient sentence was the result of U.S. District Court Judge Mary H. Murguia not finding sufficient evidence to conclude that he planned to join a terrorist organization.

[65] He also interacted with Junaid Hussain, a British-born hacker and member of ISIL, and Mujahid Miski, an Al-Shabaab recruiter and propagandist of Muslim extremism from Minnesota, via Twitter through "secure communication".

Hussain was also the founder of a pro-ISIL hacker group called "CyberCaliphate", which was responsible for a cyber-attack on the United States Central Command's Twitter account in January 2015.

[71][72][73][74] A week prior to the attack, Simpson mentioned the "First Annual Muhammad Art Exhibit and Contest" event in a tweet sent to what is believed to be Hassan's Twitter account.

"[39] The profile photo on #texasattack was of the late American Salafi imam Anwar al-Awlaki, who had repeatedly called for violence against cartoonists who insulted the Islamic prophet Muhammad prior to being killed in a U.S. drone strike in 2011 in Yemen.

[78] According to his friends in Pakistan, he had difficulties adjusting to the American culture upon moving to the U.S.[80] He took a pre-medical course at the University of Utah starting in the fall semester of 1998, but dropped out in the summer of 2003.

[54] Previously, Abdul Kareem was investigated by the FBI in 2012 for having a terrorism training document on his computer and developing a plot to attack the Super Bowl XLIX game in Glendale, Arizona with pipe bombs.

[93][94] In August 2015, Centcom announced that it had killed Junaid Hussain in a drone strike in Syria, due to his influence in motivating lone wolf-style attacks.

[97][98][99] In December 2017, a Florida Jewish American internet troll, Joshua Ryne Goldberg, was convicted of planning the bombing of a 2015 9/11 memorial event in Kansas City.

[13] Goldberg's fake Twitter persona using the name "Australi Witness" had posted a map of the Curtis Culwell Center and urged any in the area to attack "with your weapons, bombs, or knives".

[28] U.S. Secretary of Homeland Security Jeh Johnson said: [The attack] serves as a reminder that free and protected speech, no matter how offensive to some, never justifies violence of any sort.

This attack also underscores the importance of close collaboration between federal, state and local authorities in our Nation's homeland security efforts, as well as public awareness and vigilance.Johnson urged American citizens to not "misdirect" their anger at Muslims.

[107] In the wake of the attack, the Garland Independent School District announced it would begin reviewing its policy for hosting events at the Curtis Culwell Center.

[108] On May 29, 2015, protesters staging a "Freedom of Speech" rally outside of the Islamic Community Center of Phoenix, the same mosque where Simpson and Soofi had attended, were met with counter-protests.

[111] In an interview with CNN, Geller denied that the event was intentionally provocative, criticized the media for not defending the First Amendment, and pointed out that other religions have been similarly offended but do not react violently.

The day after the attack, the U.S. Department of Justice sent an urgent firearms disposition request to Lone Wolf Trading Co. As of the date of the Tribune's report, the FBI has not released any details of the guns used by Simpson and Soofi.

[116]Also on The Kelly File, Alan Dershowitz said that "critics of Pamela Geller...should realize that while she may have intended to provoke a negative reaction from extreme Islamists, she shares something in common with civil rights leader the Rev.

Martin Luther King Jr."[117] Victor Davis Hanson wrote in an article in the National Review online magazine that "radical Islam has already cut a huge swathe out of American free speech through more than a decade of death threats."

In response to host Sean Hannity's question about whether Choudary supported an unverified ISIL fatwa[124] and posted on an anonymous message board calling for Geller's death, he replied, "This isn't Mickey Mouse or Donald Duck they were drawing.

"[125] Garland Mayor Douglas Athas said he wished Geller had not chosen his town for her event and explained, "Her actions put my police officers, my citizens and others at risk.

[126] In an interview with The New York Times, the editor of Charlie Hebdo, Gérard Biard, rejected "attempts by right-wing activists to exploit that attack for their own agendas".