The FBI still has not determined whether the suspect in the fatal shootings of five U.S. servicemen in Tennessee last week was radicalized in the run-up to the rampage, the special agent in charge of the investigation said on Wednesday.

But investigators believe that the suspect, Mohammod Youssuf Abdulazeez, acted on his own on the day of the shooting at two military facilities in Chattanooga, Edward Reinhold, special agent in charge of FBI’s Knoxville division, told a news conference.

“At this time, we’re treating him as a homegrown violent extremist,” Reinhold said. “We believe he entered the facility on his own. We do not have any indication that anyone else was assisting him on that day.”

Offering a smattering of fresh details about the investigation of last Thursday’s shooting, Reinhold told reporters all of the victims were killed by a single weapon.

Investigators know where the 24-year-old suspect purchased firearms found with him after he was killed in a firefight at a naval training center, but the FBI will not disclose that information immediately, Reinhold said.

A friend of Abdulazeez told Reuters on Saturday that the suspect bought weapons on armslist.com. Telephone calls to the online firearms marketplace were not returned.

During the press conference, the FBI provided a more detailed timeline of the events that culminated with the July 16 killing of the suspect, a 24-year-old engineer with a history of psychological issues and substance abuse.

Reinhold said the attack began when Abdulazeez sprayed a military recruiting center in a Chattanooga strip mall with bullets and drove away. He then crashed his rented car through the gate of a naval training center six miles away, exited his vehicle and began firing.

He killed four Marines outside the training center building, then entered it and mortally wounded a U.S. Navy petty officer inside. The sailor died in a local hospital two days later.

The FBI has assigned 700 to 1,000 agents to the investigation, which Reinhold said was still at an early stage. The special agent said investigators would not be able to explain any of the pieces of evidence gathered so far until their probe was complete.

Meanwhile, U.S. investigators are in Jordan to interrogate the Jordanian-American uncle of the suspect, who visited relatives in that Middle Eastern country in 2014.

Jordanian authorities arrested Assad Ibrahim Abdulazeez Haj on Friday and he was being interrogated by both Jordanian and U.S. investigators, his lawyer Abdul Qader al Khatib said by telephone.

“We are gathering clues and we need to establish whether this was a sole act or one that is linked to a wider terror network,” an unnamed Jordanian security source said.

“At this stage of the interrogation we cannot rule out anything.”