Islamist extremist at Ft. Hood?

Sen. Joe Lieberman announced Sunday that he intends to lead a congressional investigation into the mass shooting at Fort Hood, saying the attack could qualify as a "terrorist act" rooted in Islamic radicalism -- the worst since 9/11.

The Independent Democrat, who chairs the Senate Committee on Homeland Security and Governmental Affairs, said there were "strong warning signs" that the alleged gunman, Maj. Nidal Malik Hasan, was an "Islamist extremist."

"If that is true, the murder of these 13 people was a terrorist act and, in fact, it was the most destructive terrorist act to be committed on American soil since 9/11," Lieberman told "Fox News Sunday."

Nidal Malik Hasan, the Army major suspected of killing 13 people and wounding 29 others at Fort Hood, worshipped at the same mosque as two of the 9/11 terrorists.

According to the London Sunday Telegraph, Hasan attended services at the Dar al-Hijrah mosque in Great Falls, Va., in 2001 at the same time as Sept. 11 hijackers Nawaf al-Hamzi and Hani Hanjour. Funeral services for Hasan's mother also was held at that mosque.

The FBI wants to interrogate Hasan to see if he met or knew al-Hamzi or Hanjour, reports the Telegraph.

The imam at the mosque at the time Hasan attended services there was Anwar al-Awlaki, a radical cleric who has been described as a supporter of al-Qaida. A third 9/11 hijacker attended al-Awlaki's lectures in California.