One of two gunmen who opened fire with assault rifles at a Prophet Muhammad cartoon contest in Texas has been identified by a law-enforcement official as having been connected to a terrorism investigation.
The two gunmen were killed by an off-duty police officer working security at the event in the Dallas suburb of Garland on May 3.
The FBI on May 4 searched an apartment complex in Phoenix, in the southern U.S. state of Arizona, and examined two vehicles at the site.
Authorities believe the apartment belonged to one of the gunmen -- a man a federal law-enforcement official identified as Elton Simpson.
The official, who spoke on the condition of anonymity, said investigators were searching Simpson's property in connection with the case.
White House spokesman Josh Earnest said, "There is no form of expression that justifies an act of violence."
The American Freedom Defense Initiative was hosting the contest to award $10,000 for the best cartoon depicting the Prophet Muhammad.
The group's mission, according to tax records, is to act against "capitulation to the global jihad and Islamic supremacism."