Doctors and staff overseeing Hasan's training viewed him at times as belligerent, defensive and argumentative in his frequent discussions of his Muslim faith, a military official familiar with several group discussions about Hasan said. The official was not authorized to speak publicly about the meetings and spoke on condition of anonymity.
Hasan was characterized in meetings as a mediocre student and lazy worker, a matter of concern among the doctors and staff at Walter Reed Army the Medical Center and Uniformed Services University of the Health Sciences, a military medical school in Bethesda, Maryland, the official said.
The concerns about Hasan's performance and religious views were shared with other military officials considering his assignment after he finished his medical training, and the consensus was to send the 39-year-old psychiatrist to Fort Hood, the official said.
If this report is true, this is not just an ethical violation, it's a legal one, officials tell CBS News correspondent Kimberly Dozier.
More Coverage of the Tragedy at Fort Hood:
Exclusive: Inside Hasan's Apartment
No Fort Hood Executions since 1961
Fort Hood Hero Recalls "Chaotic" Scene
The Government Blame Game
FBI Searches for Missed Clues
Ft. Hood Shooting: Composure Under Fire
Radical Imam's Web Site Praises Hasan
Fort Hood Reflects, but Work Carries On
Hasan Computer Shows No Terror Ties
List of Fort Hood Dead, Wounded
Fort Hood, one of the country's largest military installations, was considered the best assignment for Hasan because other doctors could handle the workload if he continued to perform poorly and his superiors could document any continued behavior problems, the official said.
The group saw no evidence that Hasan was violent or a threat. It was more that he repeatedly referred to his strong religious views in discussions with classmates, his superiors and even in his research work, the official said. His behavior, while at times perceived as intense and combative, was not unlike the zeal of others with strong religious views. But some doctors and staff were concerned that their unfamiliarity with the Muslim faith would lead them to unfairly single out Hasan's behavior, the official said.
Some in the group questioned Hasan's sympathies as an Army psychiatrist, whether he would be more aligned with Muslims fighting U.S. troops. And there was some concern about whether he should continue to serve in the military, the official said.
Sharon Willis, a spokeswoman for the Uniformed Services University, referred questions Wednesday about Hasan to his lawyer. The attorney, John Galligan of Belton, Texas, did not immediately return a telephone call seeking comment.
The revelations about the concerns that Hasan's superiors had before sending him to Fort Hood come amid a growing debate over what warning signs the military and law enforcement officials before last week's massacre.
A joint terrorism task force overseen by the FBI learned late last year of Hasan's repeated contact with a radical Muslim cleric who encouraged Muslims to kill U.S. troops in Iraq. The FBI said in a statement late Wednesday that the task force did not refer early information about Hasan to superiors because it concluded he wasn't linked to terrorism.
The doctors and staff who discussed concerns about Hasan had several group conversations about him that started in early 2008 during regular monthly meetings and ended as he was finishing a fellowship in disaster and preventive psychology this summer, the official familiar with the discussions said.
They saw no signs of mental problems, no risk factors that would predict violent behavior. And the group discussed other factors that suggested Hasan would continue to thrive in the military, factors that mitigated their concerns, the official said.
(However, a person familiar with the discussions who spoke to NPR said there had been some talk of whether Hasan suffered from mental problems: "Put it this way, everybody felt that if you were deployed to Iraq or Afghanistan, you would not want Nidal Hasan in your foxhole," the person said.)
According to the official, records reviewed by Hasan's superiors described nearly 20 years of military service, including nearly eight years as an enlisted soldier; completion of three rigorous medical school programs, albeit as a student the group characterized in their discussions as mediocre; his resilience after the deaths of his parents early in his medical education, and an otherwise polite and gentle nature when not discussing religion.
The Army has said it has no record of enlisted service for Hasan, instead noting that his military service began when he started the medical school program in 1997.
The official said the group became increasingly concerned about Hasan's religious views after he completed two research projects that took a decidedly religious tone - one at the end of his residency at Walter Reed that advocated allowing Muslim soldiers to be released as conscientious objectors instead of fighting in wars against other Muslims, and the other as he pursued his master's degree in public health that discussed religious conflicts for Muslim U.S. soldiers.
Some in the group shared their experiences with Hasan, all telling similar stories about repeated instances when he made religion an issue.
Officials involved at various times in the meetings about Hasan included John Bradley, Walter Reed's chief of psychiatry; Scott Moran, Walter Reed's psychiatric residency program director; Robert Ursano, chairman of the Uniformed Services University's psychiatry department; Charles Engel, the university's assistant chair of psychiatry, and David Benedek, an associate professor of psychiatry at the university.
Those officials either declined to comment or did not return telephone calls and emails seeking comment Wednesday.
Meanwhile, the Pentagon has found no evidence that Hasan formally sought release from the Army as a conscientious objector or for any other reason, two senior military officials told The Associated Press. Family members have said he wanted to get out of the Army and had sought legal advice, suggesting that Hasan's anxiety as a Muslim over his pending deployment overseas might have been a factor in the deadly rampage.
Hasan had complained privately to colleagues that he was harassed for his religion and that he wanted to get out of the Army. But there is no record of Hasan filing a complaint with his chain of command regarding any harassment he may have suffered for being Muslim or any record of him formally seeking release from the military, the officials told the AP.
The officials spoke on condition of anonymity because the case is under investigation.
Another Army official, Lt. Col. George Wright, said Wednesday that Hasan likely would have had to commit to another year in the military when he was transferred to Fort Hood earlier this summer. It is common for an officer to incur a one-year service extension when they receive a transfer to another post.