Updated: 11:29 a.m.

Senate Homeland Security and Governmental Affairs Chairman Joe Lieberman (ID-Conn.) said Sunday his panel will launch an investigation into the Army’s handling of Maj. Nidal Malik Hasan in the period leading up to Thursday’s rampage at Fort Hood, Texas, which Hasan is suspected of committing.

Lieberman, who appeared on “Fox News Sunday,— said that if reports are true that Hasan had “turned to Islamic extremism— and that this drove the attack, it would be the first major, successful terrorist attack on U.S. soil since 9/11.

Lieberman said his committee will delve into “whether the Army missed warning signs that should have led them to discharge— Hasan, saying there “should have been zero tolerance— for a soldier who was making positive statements about acts of terror.

Lieberman cautioned that “it’s premature to reach conclusions— about what motivated the gunman. But he said it was clear Hasan was “under personal stress,— and the committee would investigate the extent to which Islamic extremism motivated him.

Appearing on CBS’ “Face the Nation,— Sen. Jack Reed (D-R.I.) seemed to be waving a caution flag Lieberman’s way, saying the Senate should wait for Army investigators to finish their own probe first.

“I think we do have to look closely at what the Army has done,— Reed said. “But we have to wait for their careful investigations.— Reed said the Senate should look at “broader issues— like how the military is caring for its soldiers.

But Sen. Lindsey Graham (R-S.C.), who appeared with Reed, said the Senate had already “thrown a lot of money— at programs to deal with problems like post-traumatic stress disorder. Graham added that he trusts “the Army to want to fix— problems that may have caused it to miss signals that Hasan could be dangerous.