Nov. 8 (Bloomberg) -- A U.S. Senate panel will investigate motives in the deadly shooting at Fort Hood and whether any warning signs should have led to the suspect’s discharge from the Army, Senator Joe Lieberman said.

The suspect, Major Nidal Malik Hasan, an Army psychiatrist, was in intensive care with gunshot wounds after he allegedly went on a shooting rampage Nov. 5 inside the Army base in Texas, killing 13 people and injuring 30.

Lieberman, chairman of the Homeland Security and Governmental Affairs Committee, said his panel will conduct an investigation into Hasan’s motives that also will “ask whether the Army missed warning signs that should have led them to essentially discharge him.”

Hasan, 39, was in stable condition and breathing without the assistance of a ventilator, Colonel John Rossi said today in a televised briefing from Fort Hood. He declined to discuss Hasan’s activities the day of the shooting, only to say he was “preparing for his very near deployment, at the end of the month.”

Lieberman said alleged past statements by Hasan justifying suicide bombings, along with witness reports that he shouted “Allahu Akbar,” or God is great, while firing, raise concerns that the suspect had become “self-radicalized” and that authorities should have dealt with him before the shooting.

‘A Terrorist Act’

“If the reports that we’re receiving of various statements he made, acts he took, are valid, he had turned to Islamist extremism,” Lieberman, a Connecticut independent, said on the “Fox News Sunday” program. “If that is true, the murder of these 13 people was a terrorist act.”

General George Casey, the U.S. Army Chief of Staff, said the investigation needs to continue before anyone can speculate on motives. Asked on ABC’s “This Week” by host George Stephanopoulos whether it’s unknown if the shooting was a terrorist act or a case of someone who just “snapped,” Casey replied, “You are exactly right, and I don’t think we should speculate on one or the other, or any other possibilities.”

Casey, when asked about the role Hasan’s Muslim faith may have played in the shooting, said the issue was something “we need to be very careful about.”

“The speculation could potentially heighten backlash against some of our Muslim soldiers,” Casey said. “What happened at Fort Hood was a tragedy, but I believe it would be an even greater tragedy if our diversity becomes a casualty here.”

Caution on Overreacting

Senator Lindsey Graham, a South Carolina Republican, said on CBS’s “Face The Nation” that the investigation should examine whether “clear signals” were missed and that the evidence trail should be followed without overreaction.

“At the end of the day, maybe this is just about him,” Graham said of Hasan. “It’s certainly not about his religion, Islam. It’s not about the Army. It’s not about the war.”

Senator Jack Reed, a Rhode Island Democrat, said on the same program that there are about 3,000 men and women of Muslim faith serving in the military, and that some have been wounded and others killed in the U.S. wars in Iraq and Afghanistan.

“This is not about theology,” Reed said. “I think, again, what we will find is that someone who has deep psychiatric problems, they’re not unique to the Army.”

President Barack Obama and his wife, Michelle, will travel to Fort Hood Nov. 10 to attend a memorial service. U.S. Attorney General Eric Holder said Hasan may be tried by a military rather than a civilian court.

To contact the reporter on this story: John Hughes in Washington at jhughes5@bloomberg.net

Last Updated: November 8, 2009 14:33 EST