Federal, state and local law enforcement authorities are digging into the life and history of MohammodAbdulazeez, trying to find clues that might explain why the 24-year-old went on a shooting spree at two military offices in Chattanooga on Thursday.
At a press briefing Friday, FBI agent Ed Reinhold told reporters that Abdulazeez had at least two "long" guns, such as rifles or shotguns, and at least one handgun. He declined to elaborate.
At least some of the guns were purchased illegally, Reinhold added. Investigators are still analyzing evidence collected at the crime scenes, and looking into Abdulazeez's computer and travel records.
Terrorism is being investigated as a possibility in the case, according to both Reinhold and U.S. Attorney Bill Killian. But the incident has not been classified as terrorism. Abdulazeez had no known links to terror groups.
Just before 11:00 a.m. Thursday, police say Abdulazeez pulled up to a military recruiting office in a strip mall on Lee Highway. Witnesses say he began firing into the building with a high-powered rifle.
From there, police pursued him to a Navy-Marine training facility seven miles away, where investigators say he opened fire again, killing four Marines and wounding three other people, including a Chattanooga police officer. Abdulazeez was cut down by officers' bullets. He was not wearing a bulletproof vest, Reinhold said.
Authorities say they believe Abdulazeez acted alone.
"Lives have been lost from some faithful people who have been serving our country," said Gov. Bill Haslam in a Thursday statement, "and I think I join all Tennesseans in being both sickened and saddened by this."
Haslam later traveled to Chattanooga, and spoke with investigators and local leaders. He also ordered flags at state government buildings lowered to half-staff Friday.
Calling the shootings "incomprehensible", Chattanooga Mayor Andy Berke referred to the day's events as "a nightmare for the city of Chattanooga."
Speaking from the Oval Office, President Barack Obama remarked, "It is a heartbreaking circumstance for these individuals who have served our country with great valor to be killed in this fashion."