9:45 p.m. CDT
The Dallas Morning News reports that Sharon Soofi, the mother of suspected gunman Nadir Soofi, says she had no idea her son would turn to violence.
Sharon Soofi tells the newspaper her son was raised "in a normal American fashion" and was "very politically involved with the Middle East."
She says she doesn't know if "something snapped."
Sharon Soofi tells the newspaper: "He put his son above everything, I thought. The hard thing is to comprehend is why he would do this and leave an eight-year-old son behind."
Authorities shot and killed Nadir Soofi and another man outside the Curtis Culwell Center in Garland, Texas, on Sunday night. Police say they opened fire on an unarmed security guard outside a Prophet Muhammad cartoon contest.
8:15 p.m. CDT
The family of one of the gunmen killed outside a Prophet Muhammad cartoon contest in Texas says it's "struggling to understand how this could happen."
Phoenix law firm Osborn Maledon says it is representing the family of Elton Simpson, who a federal official has identified as one of the gunmen. The firm released a statement Monday on behalf of the family.
The statement says: "We are sure many people in this country are curious to know if we had any idea of Elton's plans. To that we say, without question, we did not."
The statement, which does not identify the relatives, also says the family is "heartbroken and in a state of deep shock" and sends prayers to everyone affected by this "act of senseless violence," especially the security guard who was injured.
Authorities shot and killed the two gunmen outside the Curtis Culwell Center on Sunday night after they opened fire on an unarmed security guard.
5:30 p.m. CDT
Texas police now say SWAT team officers were involved in the shooting that left two gunmen dead outside a Prophet Muhammad cartoon contest in suburban Dallas.
Garland police spokesman Joe Harn said Monday that a single police officer subdued the two gunmen, but that after his initial shots, SWAT officers nearby also fired at the two men. Harn said police don't know who fired the lethal shots.
Police stopped the two gunmen far away from the entrance to the Curtis Culwell Center, where attendees were about to leave a controversial contest displaying cartoons of the Prophet Muhammad.
Harn did not identify the officer who initially shot the two gunmen.
Officers were still posted outside the building Monday.
5 p.m. CDT
The U.N. secretary-general's office says Ban Ki-moon condemns the attack outside a Prophet Muhammad cartoon contest in Texas.
Ban's office issued a statement Monday saying he believes "such criminal acts have nothing to do with religion or belief" and "ideas must only be defended through democratic debate and dialogue."
Authorities say two men opened fire in a Dallas suburb outside the contest. The deliberately provocative contest had been expected to draw outrage from the Muslim community.
Ban's office said there is no justification for violence and Ban believes intercultural dialogue and respect are crucial means to prevent and address extremism.
3:50 p.m. CDT
A mosque president in Phoenix says a man who a federal official has identified as one of the gunmen who opened fire outside a Prophet Muhammad cartoon contest has worshipped there for about a decade.
But Islamic Community Center of Phoenix president Usama Shami says the man quit showing up over the last two or three months.
A federal law enforcement official identified one of the suspects in the shooting as Elton Simpson.
Shami said Simpson got along with everyone at the mosque. But Shami said Simpson was rattled by an FBI investigation driven by an undercover informant who infiltrated the mosque.
According to court documents, Simpson was convicted in Phoenix of lying to the FBI in 2010, about whether he'd discussed traveling to Somalia.
3:30 p.m. CDT
A federal law enforcement official is confirming the identity of the second gunman in the shooting outside a contest for Prophet Muhammad cartoons as Nadir Soofi, according to AP reporter Eric Tucker in Washington.
Several media organizations identified Soofi as Simpson's roommate.
The official was not authorized to discuss an ongoing investigation by name and spoke on condition of anonymity.
A search of federal court records did not reveal any criminal cases brought against a man by that name.
A woman who answered the door at a suburban Kansas City address listed for Soofi's father, Azam Soofi, said the family did not want to comment. She declined to give her name.
3 p.m. CDT
A lawyer who previously represented a man who a federal official says was one of the gunmen who opened fire outside a Prophet Muhammad cartoon contest says the man was a devout Muslim and respectful of the legal process.
Arizona lawyer Kristina Sitton represented Elton Simpson, who according to court documents was convicted in Phoenix of lying to the FBI in 2011, about whether he'd discussed traveling to Somalia.
Sitton said she felt the charges were "completely trumped up," to justify the costly investigation. She said he had converted to Islam as a young man.
A federal law enforcement official identified one of the suspects in the shooting as Elton Simpson. The gunmen were fatally shot Sunday after they began firing outside a community center in suburban Dallas.
1:45 p.m. CDT
The nation's largest Muslim advocacy organization has condemned an attack by two gunmen outside a suburban Dallas venue hosting a provocative contest for Prophet Muhammad cartoons.
The Council on American-Islamic Relations said in a statement Monday that a violent response is more insulting to the Muslim faith than any cartoon. The council said "bigoted speech" can't be an excuse for violence.
Leaders emphasized the American Muslim community's support for open speech and condemned acts of terror.
The gunmen were shot and killed Sunday by a police officer after they left their vehicle outside a community center in Garland and began firing assault weapons.
Garland police spokesman Joe Harn did not say whether the two were acting in response to Sunday's event, but said, "obviously they were there to shoot people."
1 p.m. CDT
Texas Gov. Greg Abbott has called a shooting outside a contest for Prophet Muhammad cartoons a "heinous crime" and said he was being briefed by state authorities.
"We live in a country where the First Amendment is one of the paramount promises of this nation," Abbott said. "That provides people the ability to speak out to say what they want. Just as people draw cartoons mocking the governor, people may draw cartoons mocking others."
Abbott's comments to reporters came following a National Day of Prayer breakfast in Austin. He shared the stage with a first-term Republican state legislator, Molly White, who earlier this year drew rebuke for instructing aides to ask Muslims to pledge their allegiance to the U.S. if they visited her office.
1 p.m. CDT
A resident of a Phoenix apartment complex says two men who lived in the unit being searched in the investigation into a Texas shooting largely kept to themselves, but that one was friendly on occasion.
Bob Kieckhaver was among the residents of the Autumn Court Apartments who were evacuated for about nine hours from units near the one being searched.
Kieckhaver said one of the men, who had a beard and wore a Muslim prayer cap, spent time working on a black Chevy that was up for sale about two months ago. Kieckhaver said that man was quiet, while the second man who lived in the apartment would greet other residents at the mailbox. He said both men would feed stray cats on a patio.
12:15 p.m. CDT
Provocative ads from a group whose Texas contest for Prophet Muhammad cartoons drew gunfire are being removed from Philadelphia transit buses after a monthlong contract expired.
The Southeastern Pennsylvania Transportation Authority had started taking the pro-Israel American Freedom Defense Initiative's ads down on Friday and expected to have them all removed by Monday.
The ads showing a 1941 photograph of Adolf Hitler with former Arab leader Hajj Amin al-Husseini appeared on 84 buses starting last month after a federal judge ordered SEPTA to accept them.
They had the tagline: "Jew Hatred: It's in the Quran."
A rabbi and other Jewish activists pasted stickers on the sides of buses bearing the ads.
Two gunmen were killed after firing on officers outside the cartoon event Sunday in Garland, Texas. A guard was wounded.
11:45 a.m. CDT
FBI agents in Phoenix are now looking at a second vehicle parked at the complex apartment where a unit is being searched as part of the investigation into a shooting outside a Prophet Muhammad cartoon contest.
Agents had broken into a white minivan and spent hours looking at it, taking pictures and removing items. They're also examining and photographing pages of a notebook or papers in the trunk of a second vehicle, a silver sedan. The sedan is parked in a covered spot near the building where the apartment is located.
Meanwhile, other FBI agents are knocking on the doors of other apartments to interview residents as Phoenix Police Department bomb squad members wearing protective armor and helmets continue to go in and out of the apartment being searched.
11:10 a.m. CDT
A White House spokesman says the president has been informed about the shooting outside a contest for Prophet Muhammad cartoons in suburban Dallas and believes no act of expression justifies violence.
Spokesman Josh Earnest says extremists try to use expressions they consider to be offensive as a way to justify violence around the world.
Earnest says "there is no act of expression, even if it's offensive, that justifies an act of violence."
Earnest also praised the officers who responded to the Sunday night shooting, saying "we saw a pretty important and notable display of bravery on the part of first responders."
The two gunmen, armed with assault rifles, were killed after opening fire on officers outside the event. One security guard was wounded.
Earnest credits officers' courage for the incident not resulting in more injuries or deaths.
11 a.m. CDT
An Arizona man identified by a federal law enforcement official as one of the gunmen who opened fire outside a Prophet Muhammad cartoon contest in Texas has the same name as a man convicted in Arizona of lying to the FBI during a terrorism investigation.
Court documents show that a man named Elton Simpson was convicted in Phoenix of lying to the FBI in January 2010, about whether he'd discussed traveling to Somalia. According to trial testimony, Simpson is an American Muslim who became the subject of a criminal investigation in 2006 because of his association "with an individual whom the FBI believed was attempting to set up a terrorist cell in Arizona."
Simpson was convicted, but a judge ruled that prosecutors hadn't proven the false statement involved terrorism. Simpson was later sentenced to three years of probation.
A federal law enforcement official says one of two gunmen killed at the Texas event late Sunday also was named Elton Simpson. Investigators were searching Simpson's property in Phoenix in connection with the case, according to the official, who was not authorized to discuss an ongoing investigation by name and spoke to The Associated Press on the condition of anonymity.
10:30 a.m. CDT
Texas police say the officer who fatally shot two gunmen who opened fire outside a contest for Prophet Muhammad cartoons likely saved lives.
Garland Police Officer Joe Harn didn't release the name of the officer, but says "his reaction, and his shooting with a pistol, he did a good job."
Harn says officers were able to stop the two gunmen before they were able to get inside the suburban Dallas venue hosting the event and shoot anyone else.
A security guard was shot and wounded during the incident Sunday night.
10:20 a.m. CDT
A federal law enforcement official has identified one of the suspects in the shooting outside a contest for Prophet Muhammad cartoons as Elton Simpson, according to AP reporter Eric Tucker in Washington.
The official, who was not authorized to discuss an ongoing investigation by name and spoke to The Associated Press on the condition of anonymity, said investigators were searching Simpson's property in Phoenix, Arizona, in connection with the case.
Investigators believe Simpson is one of two gunmen who opened fire Sunday night outside the suburban Dallas venue hosting the contest.
Police officers shot and killed two gunmen who shot at a security officer outside the Curtis Culwell Center in Garland. The security officer was wounded in the shooting.
10:15 a.m. CDT
Police in Garland, Texas, say two men had opened fire with assault rifles on officers outside a suburban Dallas venue hosting a provocative contest for Prophet Muhammad cartoons.
Officer Joe Harn said Monday the men, killed by security officers, also had more ammunition. He said investigators searched their vehicle and detonated several suspicious items, but no bombs were found in the vehicle.
He said luggage was found in the vehicle but he wasn't sure what specifically was found amid the luggage.
Harn said the officer shot in the lower leg was the only officer hurt.
He said a security plan for the event had been developed over several months.
9:50 a.m. CDT
A resident of the Phoenix apartment complex where an apartment and a vehicle are being searched as part of the investigation into a Texas shooting is describing what he observed.
Douglas Hayes said he was watching a movie late Sunday night when noise outside prompted him to go out on his balcony, located right above where the vehicle was parked.
The 25-year-old says police cars flooded the complex and he saw SWAT team members throughout the complex.
Hayes said early Monday he heard a noise that turned out to be law enforcement personnel breaking into a parked white minivan. Hayes says the windows were broken, leaving glass scattered about.
Agents used a power saw to cut open the vehicle's back door. Hayes said agents processed the van for hours afterward.
9:30 a.m. CDT
FBI agents are searching an apartment and a vehicle at a Phoenix apartment complex as part of the investigation into the deadly shooting outside a suburban Dallas venue hosting a provocative contest for Prophet Muhammad cartoons.
Agents wearing FBI jackets could be seen going in and out of an apartment and also searching a white Chevy minivan. They took what appeared to be plastic bottles out of the vehicle.
The apartment is on the first floor of a two-story building. The area around the building is sealed off but residents could be seen walking about and standing on their balconies observing the law enforcement presence.
News media helicopters are keeping an eye on the Autumn Ridge Apartments complex, which has several hundred apartments in multiple buildings.
8:30 a.m. CDT
The FBI says agents are searching a Phoenix apartment as part of the investigation into the deadly shooting outside a suburban Dallas venue hosting a provocative contest for Prophet Muhammad cartoons.
FBI spokesman Perryn Collier on Monday confirmed the Phoenix residence is being searched for indications of what prompted the shooting Sunday that left two gunmen dead and a security officer wounded outside a center in Garland.
ABC News cites a senior FBI official in reporting that one of the gunmen, a resident of the Phoenix apartment, was known to authorities and was the subject of an investigation. The ABC report says the man was convicted five years ago of lying to federal agents about plans to travel to Africa, in an apparent attempt to join a terror group there.