The U.S. government extensively investigated a gunman who opened fire at a Prophet Muhammad cartoon contest in Texas, and prosecuted him in 2010 for lying about his intent to carry out Islamic extremist attacks, authorities said May 4.
The gunman, Elton Simpson, and his roommate and accomplice Nadir Soofi, were killed by an off-duty police officer and tactical police (SWAT) officers working security at the event in the Dallas suburb of Garland on May 3.
While Simpson was well-known to the U.S. Federal Bureau of Investigation, which had secretly recorded more than 1,500 hours of his conversations in connection with a terrorism investigation between 2006 and 2010, authorities did not know he was planning an attack on the cartoon contest, an official told the Associated Press.
Simpson and Soofi, who were wearing body armor, shot a guard in the leg. Both men were killed as their assault triggered a barrage of fire from the guard and a SWAT team at the scene. The guard was later treated for his injury at a hospital and released.
Simpson, described as quiet and devout, was being watched by law enforcement for years as a result of his social media postings. .
He is believed to have used a Twitter account to pledge loyalty to the Islamic State just before Sunday's attack in a tweet that hinted at what was to come. The account was later deleted.
Less was known about Soofi, a man with a Pakistani father who had no criminal record but shared an apartment with Simpson in Phoenix which was searched by police after the attack.
Simpson worshiped at the Islamic Community Center of Phoenix for about a decade, but stopped showing up over the last two or three months, said the mosque's president, Usama Shami.
Shami said Simpson got along with everyone at the mosque, but got rattled by the FBI investigation, which was carried out by an undercover informant who inflitrated a group of followers at the mosque and befriended Simpson.
The FBI collected information about Simpson's intentions to travel to South Africa and Somalia to wage jihad in his conversations with the informant, leading to his conviction in 2011 of lying about his intentions to an FBI agent.
A lawyer who represented Simpson in the 2010 case said he was devout and respectful. She said he had converted to Islam as a young man.
Simpson first attracted the FBI's attention in 2006 because of his ties to Hassan Abu Jihaad, a former U.S. Navy sailor who was convicted of terrorism-related charges.
Jihaad was accused of leaking details about his ship's movements to operators of a website in London that openly espoused violent jihad against the United States.
In a May 2009 conversation with the FBI informant, Dabla Deng, a Sudanese immigrant, Simpson disclosed his plans to travel to Africa to wage jihad.
"I'm telling you, man, we can make it to the battlefield. It's time to roll," he said in a recorded conversation disclosed in court records.
The largest Muslim advocacy organization in the United States condemned the Texas attack May 4, saying that a violent response is more insulting to the Muslim faith than any cartoon. The Council on American-Islamic Relations said "bigoted speech" can't be an excuse for violence.
UN Secretary-General Ban Ki-moon also condemned the attack, and said "such criminal acts have nothing to do with religion or belief."
White House spokesman Josh Earnest said, "There is no form of expression that justifies an act of violence."
The winner of the Texas cartoon contest, who won a $10,000 prize for a cartoon judged to be the best at depicting the Prophet Muhammad, said he was pleased that police killed the two gunmen.
"They came to kill us and died for it. Justice," artist Bosch Fawstin tweeted May 4.
The deliberately provocative contest had been expected to draw outrage from Muslims. According to Islamic tradition, any physical depiction of the Prophet Muhammad -- even a respectful one -- is considered blasphemous.
In light of previous attacks on cartoonists in Europe who drew the prophet, police and federal agents had planned security for months ahead of the Texas event.
Fawstin's winning entry depicts a sword-wielding Prophet in a turban shouting, "You can't draw me." In reply, a cartoon bubble portrays the artist, his hand grasping a pencil, as saying, "That's why I draw you."
While U.S. officials defended the contest as a exercise of free speech, which is protected under the U.S. Constitution, the Southern Poverty Law Center has identified the group sponsoring the contest, the American Freedom Defense Initiatve, as a "hate group."
The group's mission, according to tax records, is to act against "capitulation to the global jihad and Islamic supremacism."