 -- The alleged shooter who killed four Marines in Chattanooga briefly worked at a nuclear power plant prior to the shooting, according to a spokesman for the plant.

Mohammod Youssuf Abdulazeez was a conditional employee at the Perry Nuclear Power Plant in Ohio but the job only lasted 10 days.

Abdulazeez, who graduated from the University of Tennessee Chattanooga with an engineering degree in 2012, worked at the plant in late May 2013.

Todd Schneider, a spokesman for FirstEnergy, which runs the plant, told ABC News that he "was never granted unescorted access and never entered the secured area of the plant."

Abdulazeez's employment did not extend beyond 10 days because "it was determined that he did not meet minimum requirements for ongoing employment," Schneider said.

"During his brief conditional employment, Abdulazeez’s access was limited to an administrative office building while he received general training on company procedures," Schneider said. "He did not have access to any sensitive plant information."

When the plant recognized Abdulazeez from media reports, they say they immediately contacted the Nuclear Regulatory Commission and are cooperating with investigators, Schneider added.

News of Abdulazeez working at the nuclear plant comes a day after he gunned down four Marines in a brazen daytime attack in Tennessee.

Friends and former teachers describe 24-year-old Abdulazeez as a normal, all-American, small town high school athlete, but one who also appeared sensitive to perceived slights because of his Muslim faith and came from a purportedly abusive home.

“He was just a typical American kid in high school,” Brad Benefield, Abdulazeez’s former teacher at Red Bank High School told ABC News. “He wasn’t a loner. He definitely wasn’t friends with the entire school, but he had his wrestling teammates, generally similar people, wise guys like he was... He was just a typical American kid in high school and I think that’s what can take us back a bit.”

Benefield said of Abdulazeez’s April 2015 arrest for an alleged DUI, “that sounds like more like the kind of guy he was, a partying joker.”

Former high school classmates, teachers and coaches all described Abdulazeez as a normal kind of kid, but he was apparently aware of some stereotypical harassment for being a Muslim.

He chose “My name causes national security alerts. What does yours do?” as his senior quote in his yearbook. In 2010, Abdulazeez’s sister told a local newspaper about a few incidents of harassment when she was in school. Older photographs show Abdulazeez clean shaven or with a little scruff, but he apparently grew his beard longer beginning a few months ago.

In 2009, Abdulazeez’s mother, Rasmia, filed divorce papers claiming her husband Yousuf beat her, “at times in the presence of the parties’ children” and “sexually assaulted” her.

“On occasion, Defendant [Yousuf] has also been physically and verbally abusive towards the children, striking and berating them without provocation or justification,” say the papers filed on behalf of Abdulazeez. Yousuf also said he wanted to take a second wife, as he said was permitted under Islamic law, according to Rasmia.

But Abdulazeez’s parents appeared to reconcile and the divorce proceedings were dropped just three weeks after they began. Abdulazeez's parents have not responded to requests for comment since the shooting.

Authorities say Abdulazeez, who was born in Kuwait, opened fire on two military-related installations in Chattanooga, Tenn., early Thursday afternoon. He killed four Marines and injured three other people, before he was killed, the FBI said.

Today Rep. Michael McCaul, R-Texas and Chairman of the House Committee on Homeland Security, told reporters it was his judgment that the shooting was "an ISIS-inspired attack."

FBI Special Agent in Charge Edward Reinhold later said that the investigation is being treated as a "terrorism investigation" and will be so treated until "evidence suggests otherwise." However, he said, the FBI has not formally classified the act as "an act of terrorism" and investigators have not found evidence Abdulazeez was inspired "by anyone other than himself."

Law enforcement officials told ABC News that Abdulazeez does not appear to have been on their radar as a potential terrorist. His father, Yousuf, was put on a watchlist based on preliminary information related to terror financing, but he was later cleared and removed from the list, a senior U.S. official told ABC News.

'Who He Was Isn't Who He Is Now'

Kagan Wagner, a childhood friend of Abudulazeez, said she was in class with him when the jetliners struck the World Trade Center towers on Sept. 11, 2001.

“I think in the days after that he got a little quieter and a little sadder, but I don’t think it affected him in any deep profound way that’s different than the way it affected the rest of us,” she said.

Wagner, who said her husband is active duty military, remembered Abdulazeez as a “friendly, outgoing kid,” but obviously something changed in him.

“Given the fact that he killed and injured Marines… it was just really hard and honestly I think it’s going to take some time to connect what he did with who he was, because obviously who he was isn’t who he is now,” she said.

In 2009, Abdulazeez flirted with mixed martial arts fighting, winning a cage match at a Chattanooga fight night. His one-time mixed martial arts trainer, Scott Schrader, told ABC News he was stunned to learn Abdulazeez was the shooter.

“It’s been kind of surreal,” Schrader said. “I said, ‘No, that’s crazy because I trained that kid.' He was a great kid. I’m kind of in the position that I mourn for the kid that he was, but I have utter contempt for the man he became.”

Abdulazeez would go on to graduate in 2012 from the University of Tennesee Chattanooga with a degree in engineering.

Abdulazeez recently worked at Superior Essex, described on its website as a “global leader in the design, manufacture and supply of wire and cable products.” A spokesperson for the company said, “We were shocked and deeply saddened that a three month employee of our Company was the gunman of the tragic incident in Chattanooga” and said the company is cooperating fully with authorities.

He also briefly worked at a nuclear power facility in Ohio -- for just 10 days -- and the company there said he was never allowed in the secured areas of the plant.

Almir Dizdarevic, another former coach of Abdulazeez, said the young man “always smiled” and told him just a month ago that everything was alright.

“Smiling, laughing, talking to me, [saying] no problems,” Dizdarevic told CNN. “It was absolutely nothing on him that would show me that he was upset about something.”

ABC News' James Hill contributed to this report.