Story highlights Hasan is accused of killing 13, wounding 32 in the 2009 Fort Hood shooting

Hasan had communicated via e-mail with Islamic cleric Anwar al-Awlaki before shooting

Officials learned Hasan was e-mailing al-Awlaki starting in December of 2008

"An interview would have been prudent," an FBI official tells a congressional hearing

An FBI counterterrorism official said Wednesday that the FBI should have interviewed accused Fort Hood shooter Maj. Nidal Hasan when it learned Hasan was communicating via e-mail with Islamic cleric Anwar al-Awlaki in Yemen.

"I believe an interview would have been prudent in this case," said Mark Giuliano, executive assistant director for the FBI's national security branch. But he added he didn't think "political correctness" was the reason Hasan was not interviewed and he said an interview may not have headed off the tragedy in which Hasan is accused of killing 13 and wounding 32 others in November 2009.

Giuliano is the first FBI official to testify before Congress since an independent commission's report was made public on July 19 that examined how the FBI handled information that came up while the agency was investigating al-Awlaki, a U.S.-born cleric who U.S. officials say became a key figure in al Qaeda in the Arabian Peninsula.

Some members of Congress have questioned whether the FBI and military officials acted aggressively enough when officials learned Hasan was e-mailing al-Awlaki starting in December of 2008. The commission, headed by former FBI Director William Webster, said that members of a joint terrrorism task force in San Diego had passed the information on to FBI officials in Washington and were upset no one from the FBI's Washington field office had been sent to interview Hasan.

According to the commission report, one of the San Diego agents said he had been told by Washington that the field office there "doesn't go out and interview every Muslim guy who visits extremist websites."

The San Diego agent, who was paraphrasing a phone conversation with a counterpart in Washington, said the field office had examined Army records regarding Hasan and knew he was doing research on Islam and military service while he was at Walter Reed Medical Center.

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"This guy has a legitimate work-related reasons to be going to these sites and engaging these extremists in dialogue," the San Diego agent said he was told by Washington. Furthermore, the San Diego agent said the agent in Washington described the subject as "politically sensitive" for the Washington office.

Hasan and al-Awlaki exchanged 18 e-mails between December 2008 and June 2009, but the task force in San Diego only passed two of the messages on to Washington, according to the Webster report.

In a hearing before a House appropriations subcommittee, Rep. Frank Wolf, R-Virginia, worried that political correctness might have been an issue and said he would still like to talk to officials at the FBI's Washington field office about what happened.

"An active duty member of the military communicating with a known radicalizer and recruiter should have been taken more seriously than it was," said Wolf.

Wolf also wanted to know exactly what the FBI knew about al-Awlaki at the time Hasan was e-mailing with him and if al-Awlaki had prior knowledge of the 9/11 attacks since he had served in mosques in a Washington suburb and in San Diego where a few of the 9/11 hijackers had gone to worship.

"We interviewed al-Awlaki after 9/11 on three separate occasions," said Giuliano. "He identified one of the 9/11 hijackers as somebody he knew as going to his mosque. We were never able to obtain a stitch of evidence that showed al-Awlaki knew beforehand about 9/11 or supported the 9/11 hijackers."

Wolf also asked why al-Awlaki was allowed to return to the United States in 2002 when there was an arrest warrant issued for him that was subsequently dropped. Guiliano said it was not an FBI arrest warrant but a warrant from the State Department's diplomatic security service for passport fraud.

He said the U.S. attorney's office in Colorado concluded the charge couldn't be proven in court.

"Certainly, if we felt that warrant was good and there was a way we could have incarcerated Anwar al-Awlaki at the time, we would have done that," said Guiliano.

Guiliano also noted that al-Awlaki seemed to change over the years, including a period in 2006 and 2007 when he was in prison in Yemen. After that, the FBI official said, al-Awlaki "began to be more of a propagandist, began to show more radical tendencies."

But he added the FBI did not believe he was involved in terrorist operations at that time. U.S. officials believe al-Awlaki played an important role in the failed December 2009 underwear bomb plot and also the thwarted October 2010 cargo bomb plot.

Al-Awlaki was killed September 30, 2011, by a drone strike in Yemen.

The Webster report on the Fort Hood shooting identified numerous problems in several areas including information sharing, failure to follow up on leads, failure of FBI headquarters to settle differences between the two field offices working the Hasan leads and computer technology issues.

Guiliano and other FBI officials said they began making changes right after the Fort Hood shooting.

Hasan is scheduled to undergo a military trial beginning August 20 in Texas.