Hasan is accused of entering the Soldier Readiness Center at Fort Hood on Nov. 5, 2009, and opening fire with two pistols, killing 13 people.
FBI counterterrorism official Mark Giuliano, an executive assistant director for the FBI's national security branch, said Wednesday he didn't think political correctness was the reason Hasan was not interviewed, CNN reported.
"I believe an interview would have been prudent in this case," he said.
Giuliano is the first FBI official to testify before Congress since a report was released July 19 detailing the two-year investigation by former FBI Director William Webster which concluded FBI agents' mistakes were unintentional and they should not be held responsible or punished for failing to prevent the shooting.
The review found FBI agents on the San Diego Joint Terrorism Task Force were aware Hasan had contacted known terrorist Anwar al-Awlaki in Yemen numerous times before the Fort Hood shootings and discussed the killing of civilians. But the review said the FBI agents did not bring the e-mails to the attention of the Defense Department.
Hasan wasn't interviewed, a Washington agent told the FBI in San Diego, because the Washington field office "doesn't go out and interview every Muslim guy who visits extremist Web sites," CNN reported.
Hasan is in jail awaiting court-martial on 13 charges of premeditated murder and 32 charges of attempted premeditated murder.