Updated

The Army psychiatrist suspected of killing 13 people in a shooting rampage at Fort Hood had "more unexplained connections to people being tracked by the FBI" than just a radical Muslim imam, investigators have found, according to a report.

The names of the individuals Maj. Nidal Malik Hasan was in contact with was not revealed by the official, but sources in Congress told ABC News their names and locations will likely emerge soon.

The mystery over whether the military knew Hasan was communicating with radical imam Anwar al-Awlaki lapsed into finger-pointing ahead of congressional investigations looking into the Army psychiatrist's contacts with 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 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.

The senior defense official said 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 this view was based upon what the Pentagon knows now.

Hours later, the same senior defense official reiterated that the Defense Department was not notified before the Fort Hood massacre of investigations into Hasan, despite the participation of two Defense Department investigators on two joint task forces run by the FBI that looked at Hasan. This defense official asserted that the task force ground rules barred any members from telling their home agency about task force findings without approval of the other investigators and wasn't aware of whether there was ever any discussion of doing that.

FBI officials were not immediately available to comment late Tuesday on what ground rules prevailed in the joint task forces or whether they were applied in this situation or not. One government official, however, pointed out that to complete the assessment the Defense Criminal Investigative Service representative had to access Hasan's Defense Department personnel file and determine what research he was conducting at the time.

The FBI has opened its own internal review of how it handled the early information about Hasan. Military, law enforcement and intelligence agencies also are defending themselves against tough questions about what each of them knew about Hasan before he allegedly opened fire in a crowded room at the huge Army post.

The Associated Press contributed to this report.