New Delhi, Nov. 30 -- US authorities believe the man suspected of fatally shooting a National Guard member and wounding another in Washington, DC, was radicalized while living in the United States, Homeland Security Secretary Kristi Noem said.

Noem, speaking to NBC's Meet the Press, said investigators are still gathering information on the suspect's motive. "But I will say we believe he was radicalized since he's been here in this country," she said.

"We do believe it was through connections in his home community and state, and we're going to continue to talk to those who interacted with him, who were his family members. So far we've had some participation."

Federal authorities have identified the suspect as Rahmanullah Lakanwal, 29, a...