WASHINGTON — The mystery over whether the military knew Fort Hood shooting suspect Nidal Hasan was communicating with a radical Muslim imam lapsed into finger-pointing ahead of congressional investigations looking into the Army psychiatrist's contacts with any extremists.

Even as President Barack Obama remembered those killed at the Texas Army post and condemned what he described as "the twisted logic that led to this tragedy," federal agencies reacted to conflicting claims about whether a Defense Department terrorism investigator looked into Hasan's contacts months ago with Anwar al-Awlaki. Awlaki, an imam who was released from a Yemeni jail last year, has used his personal Web site to encourage Muslims across the world to kill U.S. troops in Iraq. A military official Tuesday denied knowing Hasan had such contacts.

Two government officials, speaking on condition of anonymity because they were not authorized to discuss the case on the record, said the Washington-based joint terrorism task force overseen by the FBI was notified of communications between Hasan and the imam overseas, and the information was turned over to a Defense Criminal Investigative Service employee assigned to the task force. The communications were gathered by investigators beginning in December 2008 and continuing into early this year.

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 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 last Thursday — a familiar, early stage in the investigation of headline-grabbing crimes when public officials involved in a case often speak anonymously as they try to shift any blame to rivals in other agencies.

The Senate already has launched its own inquiry into the Hasan case. Sens. Joe Lieberman, a Connecticut independent, and Susan Collins, R-Maine, plan to hold a hearing on the shootings next week.

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