A law enforcement official said that Mr. Rahim had become radicalized by militant Islam social media sites and that he posed an “imminent threat” on the morning that he was confronted.
Coming just a month after two Muslim men with ties to the Islamic State were shot and killed while trying to attack an anti-Islamic gathering in Garland, Tex., the case has also renewed concerns in Washington about the long reach of the Islamic State and other radical groups that have seized on Internet recruitment.
“These cases are a reminder of the dangers posed by individuals radicalized through social media,” said the chairman of the House Homeland Security Committee, Representative Michael McCaul, Republican of Texas, at a hearing on Wednesday. He added that Mr. Rahim had been under investigation because he was “communicating with and spreading ISIS propaganda online.”
