A radical American imam who communicated with the Fort Hood shooting suspect and called him a hero was once arrested in Yemen on suspicion of giving religious approval to militants to conduct kidnappings.
Yemeni authorities are now hunting for Anwar al-Awlaki to determine whether he has al-Qaida ties.
Al-Awlaki, who has used his personal Web site to encourage Muslims around the world to kill U.S. troops in Iraq, disappeared in Yemen eight months ago, according to his father. Yemeni security officials say they believe he is hiding in a region of the mountainous nation that has become a refuge for Islamic militants.
After his arrest in 2006, investigators were unable to prove any links to al-Qaida, and he was released in late 2007, according to two Yemeni counterterrorism officials and an Interior Ministry official. They spoke Tuesday on condition of anonymity because they were not authorized to talk to the press.
Fort Hood massacre
Maj. Nidal Malik Hasan is accused of killing 13 people in a rampage at the Fort Hood Army post in Texas. He communicated with al-Awlaki in e-mail exchanges 10 to 20 times over several months last year, according to a U.S. investigative official in Washington and Rep. Pete Hoekstra of Michigan, the top Republican on the House Intelligence Committee.
The communications, which were intercepted by the FBI, consisted primarily of Hasan posing questions to the imam as a spiritual leader or adviser, and their content was "consistent with the subject matter of (Hasan's) research," a law enforcement official said. The law enforcement and investigative officials spoke on condition of anonymity because they were not authorized to discuss the case.
In the Army, Hasan was working with patients suffering from post-traumatic stress disorder stemming from U.S. combat operations in Iraq and Afghanistan. Associates and relatives have said he was disturbed that U.S. Muslim soldiers could fight against fellow Muslims in those countries.
The FBI investigated at the time and concluded that Hasan was not a threat. And investigators say now that there is no evidence Hasan received help or orders to carry out the Fort Hood attack.
But the man to whom Hasan turned for advice has for years preached in sermons circulated on the Web that the United States was engaged in a war against Islam and urged Muslims to fight it.
'44 ways to support jihad'
In January, al-Awlaki posted an article called "44 ways to support jihad," saying that joining or helping "holy warriors" fight the U.S. and its allies is "obligatory for every Muslim." The article encouraged Muslims to donate and raise money for mujahedeen and to encourage people to join.
The 38-year-old al-Awlaki, a U.S. citizen born in New Mexico to Yemeni parents, preached at a Virginia mosque that Hasan's family attended.
He has had several encounters with al-Qaida figures. In 2000, he met two of the 9/11 hijackers, Khalid al-Midhar and Nawaf al-Hazmi, at a San Diego mosque where al-Awlaki was a preacher. The U.S. government's 9/11 Commission report says the men "respected al-Awlaki as a religious figure and developed a close relationship with him." They were aboard the plane that crashed into the Pentagon.
The FBI investigated al-Awlaki in 1999 and 2000 after learning he may have been contacted by a possible "procurement agent" for Osama bin Laden. His telephone number was also found when police raided the Hamburg, Germany, apartment of Ramzi Binalshibh, a Yemeni al-Qaida figure believed to have been a key facilitator of the 9/11 attacks, according to the commission report.
After he returned to Yemen in 2002, al-Awlaki taught at San'a's Iman University, the same university that John Walker Lindh, the American caught with the Taliban in Afghanistan, used to visit while living in Yemen. The university is headed by Abdulmajid al-Zindani, a prominent Yemeni cleric often described as a religious mentor to bin Laden.
Al-Awlaki was arrested in 2006 with a group of five Yemenis accused of kidnapping a Shiite teenager for ransom, according to the Yemeni counterterrorism and Interior Ministry officials. Al-Awlaki was the group's spiritual leader and had issued a fatwa, or religious decree, permitting them to kidnap foreigners and rich Yemenis, the officials said.
The group also plotted to kidnap the U.S. military attache in Yemen and rented a villa near the attache's house using a fake ID, the officials said. There was no immediate confirmation of the plot from American officials.
But investigators could not find any evidence for al-Qaida ties. Tribal leaders — who hold enormous influence in Yemen, where the central government is weak — intervened and pushed for the group's release, the Interior Ministry official said. The group was freed in December 2007 after they signed documents promising to remain in Yemen and to avoid any contacts with militants.
But authorities' suspicions over al-Awlaki were raised again several months after his release because he stopped checking in regularly with security officials as required under his release agreement, the officials said. Also, months later, another member of the group arrested with al-Awlaki left Yemen and was arrested in Syria on terrorism charges.
In response, al-Awlaki was put on a wanted list on suspicion of possible al-Qaida links, the Interior Ministry official said.
He and the counterterrorism officials said al-Awlaki is believed to be hiding in Yemen's Shabwa or Mareb provinces, which along with Jof province make up the so-called "triangle of evil" because of a heavy presence of al-Qaida militants. Fighters from the terror organization have been increasingly entering Yemen and finding refuge among tribes disgruntled with the central government.
Still, al-Awlaki appears to be maintaining his Web site. On Monday, he posted a statement declaring that Hasan "is a hero. 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."
An official told NBC News that in addition to his website, he also has a popular Facebook page with more than 5,100 friends. The official, who requested anonymity, said al-Awlaki had been intermittently on both the Yemeni terrorist "watch list" and "under house arrest" throughout 2008 and 2009.
Al-Awlaki's father, Nasser al-Awlaki, told The Associated Press on Tuesday that he has not had any contact with his son in eight months and did not know his location. Anwar's wife and five children — three boys and two girls — are staying with Nasser al-Awlaki, he said.
The father, who was studying agriculture in the U.S. when Anwar was born and later served as Yemen's agriculture minister, insisted his son has no links with al-Qaida.
"He has nothing to do with al-Qaida. But he's a devout Muslim. He has never been involved in anything against anybody," he said.
The Associated Press and Robert Windrem and Garrett Haake of NBC News contributed to this report.