The two government officials, speaking on condition of anonymity, said that the Washington-based joint terrorism task force overseen by the FBI was notified of communications between Hasan and a radical imam overseas, and the information was turned over to a Defense Criminal Investigative Service employee assigned to the task force.

That Defense investigator wrote up an assessment of Hasan after reviewing the communications and the Army major's personnel file, according to these officials. The assessment concluded that Hasan did not merit further investigation - in large part because his communications with the imam were centered on a research paper about the effects of combat in Iraq and Afghanistan, and the investigator determined that Hasan was in fact working on such a paper, the officials said.

The disclosure came as questions swirled about whether opportunities were missed to head off the massacre in which 13 died and 29 were wounded Thursday.

The disclosure yesterday of the defense investigator's role indicated that the U.S. military was aware of worrisome behavior by the massacre suspect long before the attack. Just hours later, a senior defense official, also demanding anonymity, directly contradicted that notion.

The senior defense official said that neither the Army nor any other part of the Defense Department knew of Hasan's contacts with any Muslim extremists. But the defense official carefully conceded that this view was based upon what the Pentagon knows now.