Investigators are trying to understand why the Kuwait-born man opened fire on the U.S. military sites and raised the specter of terrorism on U.S. soil. Abdulazeez did not appear to have been on the radar of federal authorities before the bloodshed Thursday, officials said. But now counterterrorism investigators are taking a deep look at his online activities and foreign travel, searching for clues to his political views or influences.

The gunman opened fire Thursday at a Marine-Navy reserve facility. The FBI, which is leading the investigation into the attacks, said he was wearing a load-bearing vest that allowed him to move about while carrying additional ammunition.

The U.S. Attorney in eastern Tennessee said the attacks were being treated as a terrorism investigation. Bill Killian said Thursday that investigators will “let the facts and the evidence lead us where it may.”

A relative of Abdulazeez said he has family in the West Bank and that he visited Jordan last year.

The relative, who spoke on condition of anonymity because the person feared repercussions, said Abdulazeez was a “nice, educated guy.” Abdulazeez met the relative for the first time during his visit to Jordan last year, and the two spoke for about an hour. During that time, the relative saw no hints of violence.

The relative said his parents are both from the West Bank and that the family are mainstream Muslims, not fundamentalists. The person says “they fast, they pray and that is it.”

Residents in the quiet neighborhood in Hixson, Tennessee, where Abdulazeez lived in a two-story home, said they would see him walking along the wide streets or doing yard work. One neighbor recalled Abdulazeez giving him a ride home when he became stranded in a snowstorm.

“It's kind of a general consensus from people that interacted with him that he was just your average citizen there in the neighborhood. There was no reason to suspect anything otherwise,” said Ken Smith, a city councilman who met with neighbors Thursday night.

Abdulazeez's mother, Rasmia Ibrahim Abdulazeez, filed a divorce complaint in 2009 accusing her husband, Youssuf Saed Abdulazeez, of beating her repeatedly in front of their children and sexually assaulting her. She also accused him of “striking and berating” the children without provocation.

Weeks later, the couple agreed to reconcile, with the father consenting to go to counseling.

Abdulazeez graduated from Red Bank High School in Chattanooga, where he was on the wrestling team.

Abdulazeez got an engineering degree from the University of Tennessee at Chattanooga in 2012 and worked as an intern a few years ago at the Tennessee Valley Authority, the federally owned utility that operates power plants and dams across the South.

He was conditionally hired as an engineer at the Perry nuclear power plant near Cleveland and spent 10 days there before he was let go in May 2013 because he failed a background check, said Todd Schneider, a FirstEnergy Corp. spokesman. Schneider would not say why.

Later on Friday, a federal official who had been briefed on the matter told The Associated Press that Abdulazeez was dismissed because he failed a drug test. The official spoke on condition of anonymity because of the ongoing law enforcement investigation.

For the last three months, he had been working at Superior Essex Inc., which designs and makes wire and cable products.

In April, he was arrested on a drunken driving charge, and a mugshot showed him with a bushy beard.

Karen Jones, who lived next to the family for 14 years, said she was somewhat surprised last weekend by his appearance when she saw him walking with another man in woods behind the house, where he liked to shoot pellet guns at a red target suspended in a tree.

“He had this big beard, which was not how he used to be,” Jones said. She said he was typically clean-shaven.

The women of the family always wore head coverings in accordance with their Muslim faith, Jones said, and the father works for the city of Chattanooga. Two women led away from the home after the shootings Thursday were also in headscarves.

Sam Plank graduated from Red Bank High two years before Abdulazeez but hadn't crossed paths with him since 2006. “Obviously something has happened since then,” he said. “He was as Americanized as anyone else. At least that's what it seemed like to me.”

Another Red Bank High graduate who knew him, Hussnain Javid, said Abdulazeez was “very outgoing,” adding: “Everyone knew of him.”

Javid, a 21-year-old student at the University of Tennessee at Chattanooga, said he occasionally saw Abdulazeez at the Islamic Society of Greater Chattanooga, but the last time was roughly a year ago.

The official Kuwait News Agency on Friday quoted the Interior Ministry as saying that while Abdulazeez was born in Kuwait, he was of Jordanian origin. The report also said he traveled to Kuwait and Jordan in the spring of 2010.

For months, U.S. counterterrorism authorities have been warning of the danger of attacks by individuals inspired but not necessarily directed by the Islamic State group. Officials have said they have disrupted several such lone-wolf plots.

A federal law enforcement official said authorities were searching Abdulazeez's computer but had not found an extensive online presence and had not uncovered any evidence he was directly influenced by the Islamic State. The official was not authorized to discuss the case publicly and spoke on condition of anonymity.

The gunman on Thursday sprayed dozens of bullets at a military recruiting center at a strip mall in Chattanooga, then drove to a Navy-Marine training center a few miles away and shot up the installation. The bullets smashed through windows and sent service members scrambling for cover.

In addition to the Marines killed, three people were wounded, including a sailor who was seriously hurt.

The dead were identified Friday by the Marines as Gunnery Sgt. Thomas J. Sullivan of Hampden, Massachusetts; Staff Sgt. David A. Wyatt of Burke, North Carolina; Sgt. Carson A. Holmquist of Polk, Wisconsin; and Lance Cpl. Squire K. “Skip” Wells of Cobb County, Georgia. Sullivan, Wyatt and Holmquist had served in Iraq, Afghanistan or both.

Gen. Ray Odierno, the Army's top officer, said that security at military recruiting and reserve centers will be reviewed, but that it is too early to say whether they should have security guards or other increased protection.

Odierno said there are legal issues involved in allowing recruiters to carry guns. And he said the centers need to be open and accessible to the public. (AP)