UPDATED | May 4, 2015 3:05 PM

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GARLAND (CBSDFW.COM) – An event in Garland on Sunday night took a deadly turn as two suspects began firing shots outside of the Curtis Culwell Center during a Muhammad art exhibit. Police officers killed those men and are now trying to determine who they were and what their motivation might have been.

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The event, called the First Annual Muhammad Art Exhibit and Contest, was held in the same place where a Stand With the Prophet conference was held in January. It featured adaptations of the Islamic prophet. Approximately 200 people were in attendance at around 6:30 p.m. when the shooting incident began.

CBS 11 News was the first to confirm the deaths of the suspects. Shortly after a lockdown, organizer Pamela Geller said that two men were shot dead, and an officer was shot in the leg.

Timeline Of The Attack

CBS 11 News reporter Gabriel Roxas was there to report on the exhibit even before the chaos erupted, and was inside of the building during the gunfire.

Authorities stated that the suspects pulled up to the front of the center with assault rifles and fired shots at a Garland Independent School District security guard. The unarmed guard, later identified as Bruce Joiner, was struck in the leg and taken to a nearby hospital. He has since been released.

Bruce Joiner (credit: Facebook)

Bruce Joiner (credit: Facebook)

A traffic officer heard the shots and returned fire. The officer killed both men near their car with his duty pistol, despite the suspects wearing body protection of some type. There was concern that a bomb may have been inside of the car that the suspects drove to the event. A bomb unit was brought in to check out that vehicle, but no bombs were found.

Meanwhile, the FBI conducted a search at an apartment complex in Phoenix where the suspects lived. Authorities are not sure when the men arrived in North Texas, but they had luggage in the truck of the car. The luggage was detonated safely at the scene early Monday.

Early Monday one of the suspects was identified as Elton Simpson. He was the subject of a previous terror investigation. He was charged in 2010 with making false statements to federal agents in regards to a Somalia trip. He was traveling there “for the purpose of engaging in violent jihad,” according to the charges, and was found guilty in March 2011 of making a false statement. But the court ruled that there was “insufficient evidence to support that the false statement ‘involved’ international terrorism.”

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Simpson was given three years probation and a $600 fine, and the case was closed in September 2011.

Later Monday afternoon the second shooter was identified as Nadir Soofi. Officials say he does not have a history with federal law enforcement, but is the roommate of Simpson.

Grand Jury Indictment Against Simpson

Police on Monday are continuing to piece together everything that led up to the shooting. Prior to the attack, messages concerning radical Islamic viewpoints were posted on social media pages from two accounts.

Police in Garland said that they had been monitoring the situation and were prepared, but had been unable to confirm that something would actually happen. “What’s surrounded these type of events in other parts of the world, additional security was added to this event,” said Joe Harn with the Garland Police Department. “Luckily, it was.”

During a Monday news conference, Harn added that $10,000 was spent on extra security for the art event, and officials started planning for potential issues months ago. In regards to the officer who shot and killed the suspects, Harn said, “Under the fire he was put under, he did a very good job and probably saved lives,” as it appears that the suspects were intent on getting inside the building and killing attendees.

Several businesses — Walmart, Sam’s Club, Taco Bell, Academy — are located near the shooting site, and people inside of those stores heard the gunfire. The buildings were immediately evacuated, and witnesses watched and waited as the bomb squad combed over the area. After closing early, those stores opened again on Monday.

This was also close to Naaman Forest High School, and the Garland Indpendent School District has been working with the police department to determine the safest course of action. Advanced placement testing scheduled for Monday has been moved, but students were told to report to the campus for regular classes.

“It’s crazy that it’s so close to home, over controversial art,” said Jennifer Bohannon, who lives near the shooting site. “I don’t understand what happened. It’s real scary. I have kids. It’s crazy how the world is right now.”

“You don’t experience that very often, but it’s going to happen,” said Kendal Woodham, who also lives nearby. “It could happen anywhere.”

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Gov. Greg Abbott issued a statement late Sunday night that said, “Texas officials are actively investigating to determine the cause and scope of the senseless attack in Garland, Texas. This is a crime that was quickly ended thanks to the swift action by Garland law enforcement. Our thoughts and prayers remain with all those affected.”