Unravelling Chattanooga: What do we know about shooter?

The man authorities say killed four Marines in Chattanooga, Tenn., Thursday has no known connections to terrorist organizations and was seen by his peers as 'normal.'

Authorities say the man they believe killed four Marines in Chattanooga, Tenn., on Thursday had not previously been on their radar, and that no connection has been found yet tying him to an international terrorist organization.

Muhammad Youssef Abdulazeez was a 24-year-old, Kuwait-born, naturalized American. Officials and witnesses say Mr. Abdulazeez opened fire on a military recruiting center and a Navy-Marine training center several miles away. Three people were wounded, in addition to the four Marines killed.

Abdulazeez was also killed during the attack, by what a US official said was a shot fired by Chattanooga police.

Details on the motives for Abdulazeez’s attack and on the "numerous weapons" used in the attack are still unknown.

"We are looking at every possible avenue, whether it was terrorism, whether it's domestic, international, or whether it was a simple criminal act," FBI agent Ed Reinhold said.

The FBI issued the following statement Thursday:

The FBI’s Knoxville Field Office, along with the Chattanooga Police Department and other law enforcement partners, are working jointly to investigate today’s shootings at a military recruitment center and a reserve center in Chattanooga, Tennessee in which four individuals were killed and three injured. The shooter, Mohammod Youssuf Abdulazeez, 24, is also deceased. While it would be premature to speculate on the motives of the shooter at this time, we will conduct a thorough investigation of this tragedy and provide updates as they are available.

Marilyn Hutcheson, who works across the street from where one of the attacks took place, says she heard a barrage of gunfire begin around 11 am. The incident lasted about 20 minutes, she said.

"I couldn't even begin to tell you how many," Ms. Hutcheson told The Associated Press. "It was rapid-fire, like pow-pow-pow-pow-pow, so quickly. The next thing I knew, there were police cars coming from every direction."

Abdulazeez, an electrical engineering graduate from the University of Tennessee at Chattanooga, had been popular among his peers, says Hussnain Javid, who attended both high school and college with Abdulazeez.

“He was very outgoing,” Mr. Javid told AP. “Everyone knew of him.”

Another high school peer, Greg Raymond called Abdulazeez “creative” and “light-minded,” but disagreed that he was popular.

"He was a really calm, smart, and cool person who joked around. Like me, he wasn't very popular so we always kind of got along. He seemed like a really normal guy," Mr. Raymond told AP.

Residents in the neighborhood where authorities believed he lived also said they did not know Abdulazeez or his family very well.

The attacks come at a time when the US military and law enforcement officials have warned about “lone wolves” threatening domestic targets, as well as during the month of Ramadan, when the Islamic State has threatened intensified violence and has encouraged extremist attacks in the United States.

Evidence connecting Abdulazeez to the Islamic State has not been found, but the SITE Intelligence Group, which tracks extremist groups, said Abdulazeez wrote online Monday that “life is short and bitter” and that Muslims should take opportunities to “submit to Allah.”

President Obama said Thursday that a prompt investigation would ensue, and that the White House had told the Pentagon to keep military installations vigilant.

"It is a heartbreaking circumstance for these individuals who served our country with great valor to be killed in this fashion," Mr. Obama said.

This report contains material from Reuters and the Associated Press.