"That was reported by a few of the witnesses that were at the scene," Cone's deputy, Col. John Rossi, told Fox News.

Federal law enforcement officials told The Associated Press that Hasan had come to their attention at least six months ago because of Internet postings that discussed suicide bombings. The officials said they are still trying to confirm that he was the author.

One of the Web postings that authorities reviewed is a blog that equates a suicide bomber to a soldier throwing himself on a grenade to save the lives of his comrades.

"To say that this soldier committed suicide is inappropriate. Its more appropriate to say he is a brave hero that sacrificed his life for a more noble cause," the Internet posting reads. "Scholars have paralleled (sic) this to suicide bombers whose intention, by sacrificing their lives, is to help save Muslims by killing enemy soldiers."

Before Thursday's shooting, Hasan reportedly gave away all of his furniture along with copies of the Koran to neighbors, KXXV-TV reported.

Authorities have not ruled out that Hasan was acting on behalf of some unidentified radical group, a senior U.S. official in Washington said. He would not say whether any evidence had come to light to support that theory.