FBI Director James Comey says federal investigators knew that one of the two gunmen in an attempted attack outside a provocative cartoon contest in Garland was aware of the event.
Comey told reporters Thursday that agents had developed information hours before Sunday's event in Garland that Elton Simpson had an interest in it.
He said that information was distributed to local authorities in Texas, but there had been no indication that Simpson was planning an attack.
Simpson, of Phoenix, had been convicted in 2011 in a terrorism-related investigation and sentenced to probation. The FBI opened a new investigation into his activities in March. Comey said that investigation was "open but far from complete" at the time of the shooting.
Meanwhile, a lawyer for five police officers involved in the shooting says they have yet to return to work but are "doing well."
The officers killed two gunmen who had wounded a security guard at a contest about the Prophet Muhammad. The officers' names have not been released.
In a statement Thursday, lawyer Zach Horn commended the officers' "bravery and skill." He said they saved "an untold number of lives."
One officer subdued Simpson and Soofi when they opened fire outside of the contest. After the initial shots, four SWAT officers who were nearby also fired at Simpson and Soofi.