Authorities have identified two of the suspected gunmen who attacked an event in Dallas on cartoons of the Prophet Muhammad, US media reports.
The FBI has named the two men as Elton Simpson and his room mate Nadir Soofi.
Simpson had previously been investigated on suspicion of terrorism offences, and was convicted several years ago for lying to authorities about his plans to travel to Somalia.
Simpson and Soofi attacked the Muhammad Art Exhibit in the Dallas suburb of Garland as the event was ending, firing assault rifles at two officers in a parking lot.
They drove to the Muhammad Art Exhibit in the Dallas suburb of Garland as the event was ending, firing with assault rifles on two officers in a parking lot.
One of the officers, a traffic policeman, returned fire and killed both the gunmen, Garland police official Joe Harn said. The security officer who with him was shot in the lower leg. He was treated in hospital and then released.
"Obviously they were there to shoot people," Mr Harn said.
The event was organised by the American Freedom Defense Initiative (AFDI), which is run by controversial blogger and activist Pamela Geller.
One of the keynote speakers was the Dutch politician Geert Wilders, an outspoken critic of Islam in Western societies.
The conference included a contest that offered a $10,000 (£6,600) prize for a cartoon of the Prophet Mohammed. Depictions of the Prophet Mohammed are offensive to many Muslims.
Officials believe that Simpson sent several Twitter messages before the Sunday's shooting, including one with the hashtag #texasattack part of which read: "May Allah accept us as mujahideen" [holy fighters]. The Twitter account was later suspended.
Simpson was convicted several years ago for lying to authorities about his plans to travel to Somalia, court documents show.
The FBI's John Lannarelli told US media that both suspects appeared to have lived in the same Phoenix apartment, although this has not been officially confirmed.
The bomb squad was called in to search the suspects' vehicle. They set off several controlled explosions around the vehicle, where they found additional ammunition but no bombs, Mr Harn said.
While he did not publicly name the men, he said that officials were confident they knew their identities.
The suspects' bodies remained at the scene on Monday morning, surrounded by dozens of empty shell casings.
Security had been tight ahead of Sunday's conference and Garland's mayor acknowledged that there had been a lot of local concern about the event, though police said there had been no credible threats.
A security plan had been put in place over several months, and event organisers paid $10,000 for additional security on the advice of the police, Mr Harn said.