In retrospect, the signs of Major Nidal Malik Hasan's growing anger over the United States wars in Iraq and Afghanistan seem unmistakable. But even people who worried that his increasingly strident views were clouding his ability to serve the US military could not predict the murderous rampage of which he now stands accused.

In the months leading to last Thursday's shooting spree at the Fort Hood army post that left 13 people dead and 29 others wounded, Hasan raised eyebrows with comments that the war on terror was "a war on Islam" and wrestled with what to tell fellow Muslim solders who had their doubts about fighting in Islamic countries.

"The system is not doing what it's supposed to do," said Dr Val Finnell, who complained to administrators at a military university about what he considered Hasan's "anti-American" rants.

"He at least should have been confronted about these beliefs, told to cease and desist, and to shape up or ship out."

Not surprised

Finnell studied with Hasan from 2007-2008 in the master's programme in public health at the military's Uniformed Services University of the Health Sciences in Bethesda, Maryland, where Hasan persistently complained about perceived anti-Muslim sentiment in the military and injected his politics into courses where they had no place.

"In retrospect, I'm not surprised he did it," Finnell said of the shootings. "I had real questions about what his priorities were, what his beliefs were."

Hasan, who was shot by civilian police and taken into custody, was in intensive care but breathing on his own late Saturday at an Army hospital in San Antonio. Officials refused to say if he was talking to investigators.

At least 17 victims remained hospitalised with gunshot wounds, and nine were in intensive care late Saturday. Yesterday, numerous church services honouring the victims were planned both on the post and in neighbouring Killeen.

Probing hasan's computer

Military criminal investigators continue to refer to Hasan as the only suspect in the shootings, but won't say when charges would be filed. "We have not established a motive for the shootings at this time," said Army Criminal Investigative Command spokesman Chris Grey.

A government official, speaking on condition of anonymity because the person was not authorised to discuss the case, said an initial review of Hasan's computer use has found no evidence of links to terror groups, or anyone who might have helped plan or push him towards the shooting attack. The review of Hasan's computer is continuing, the official said.

Army investigators yesterday were searching for additional evidence to put together a comprehensive bullet trajectory analysis. Investigators were "seeking any military or civilian personnel who may have left the scene ... with gunshot damage such as damaged privately owned vehicles," Fort Hood spokesman Chris Haug said in a statement.

Hasan likely would face military justice rather than federal criminal charges if investigators determine the violence was the work of just one person.

Senator Joe Lieberman, chairman of the Senate Homeland Security and Governmental Affairs Committee, said yesterday he plans to begin a congressional investigation to determine whether the shootings constitute a terrorist attack.

Avoiding wrong conclusions

Lieberman, an independent from Connecticut, said on Fox News Sunday that he wants to find out whether the Army missed warning signs that Hasan was becoming extreme in his Islamist views.

"If Hasan was showing signs, saying to people that he had become an Islamist extremist, the US Army has to have zero tolerance," he said. "He should have been gone."

Army Chief of Staff George Casey warned against reaching conclusions about the suspected shooter's motives until investigators have fully explored the attack.

He said on ABC television's 'This Week' that focusing on Hasan's Islamic roots could "heighten the backlash" against all Muslims in the military.

Law-abiding citizen

Hasan's family described a man incapable of the attack, calling him a devoted doctor and devout Muslim who showed no signs that he might lash out.

"I've known my brother Nidal to be a peaceful, loving and compas-sionate person who has shown great interest in the medical field and in helping others," his brother, Eyad Hasan, of Sterling, Virginia, said in a statement. "He has never committed an act of violence and was always known to be a good, law-abiding citizen."

Still, in the days since authorities believe Hasan fired more than 100 rounds in a soldier-processing centre at Fort Hood in the worst mass shooting on a military facility in the US, a picture has emerged of a man who was vehemently opposed to the wars in Iraq and Afghanistan, was trying to elude his pending deployment to Afghanistan and had struggled professionally in his work as an Army psychiatrist.