Fifteen victims remained hospitalized with gunshot wounds, and eight were in intensive care.
The personal Web site for a radical American imam living in Yemen who had contact with two 9/11 hijackers praised Hasan as a hero.
The posting Monday on the Web site for Anwar al Awlaki, who was a spiritual leader at two mosques where three 9/11 hijackers worshipped, said American Muslims who condemned the Fort Hood attack are hypocrites who have committed treason against their religion.
Awlaki said the only way a Muslim can justify serving in the U.S. military is if he intends to "follow in the footsteps of men like Nidal."
"Nidal Hassan (sic) is a hero," Awlaki said. "He is a man of conscience who could not bear living the contradiction of being a Muslim and serving in an army that is fighting against his own people."
Two U.S. intelligence officials told The Associated Press the Web site was Awlaki's. They spoke on condition of anonymity to discuss intelligence collection. Awlaki did not immediately respond to an attempt to contact him through the Web site.
Hasan's family attended the Dar al Hijrah Islamic Center in Falls Church, Va., where Awlaki was preaching in 2001. Hasan's mother's funeral was held at the mosque on May 31, 2001, according to her obituary in the Roanoke Times newspaper, around the same time two 9/11 hijackers worshipped at the mosque and while Awlaki was preaching.
Awlaki is a native-born U.S. citizen who left the United States in 2002, eventually traveling to Yemen. He was released from a Yemeni jail last year and has since gone missing. He is on Yemen's most wanted militant list, according to three Yemeni security officials.
The officials say Awlaki was arrested in 2006 with a small group of suspected al-Qaida militants in the capital San'a. They say he was released more than a year later after signing a pledge he will not break the law or leave the country. The officials spoke on condition of anonymity because of the sensitivity of the issue.
The Falls Church mosque is one of the largest on the East Coast, and thousands of worshippers attend prayers and services there every week.
Imam Johari Abdul-Malik, outreach director at Dar al Hijrah, said he did not know whether Hasan ever attended the mosque but confirmed that the Hasan family participated in services there. Abdul-Malik said the Hasans were not leaders at the mosque and their attendance was normal.
The London Telegraph first reported the potential link between Hasan and the mosque.
Sen. Joe Lieberman said Sunday he wants Congress to determine whether the shootings constitute a terrorist attack and whether warning signs that Hasan was embracing an increasingly extremist view of Islamic ideology were missed.
Classmates who participated in a 2007-2008 master's program at a military college told The Associated Press that they complained to faculty during the program about what they considered to be Hasan's anti-American views, which included his giving a presentation that justified suicide bombing and telling classmates that Islamic law trumped the U.S. Constitution.
"If Hasan was showing signs, saying to people that he had become an Islamist extremist, the U.S. Army has to have zero tolerance," Lieberman, an independent from Connecticut, said on "Fox News Sunday." "He should have been gone."
Army Chief of Staff Gen. George Casey said Sunday it's important for the country not to get caught up in speculation about Hasan's Muslim faith, and he has instructed his commanders to be on the lookout for anti-Muslim reaction to the killings at the Texas post.
Casey, who appeared on ABC's "This Week" and CNN's "State of the Union," said evidence to this point shows that Hasan acted alone.
President Barack Obama is scheduled to attend a memorial service Tuesday honoring victims of the attack. Lt. Gen. Robert Cone, the post commander, said the service will include a roll call of names of the dead and a 21-gun salute.