The Saudi student who fatally shot three people at a Florida naval base had hosted a dinner party earlier in the week where he and three others watched videos of mass shootings, a US official says.
One of the three students who attended the dinner party videotaped outside the building while the shooting was taking place at Naval Air Station Pensacola on Friday, says the US official, who had been briefed by federal authorities.
Two other Saudi students watched from a car, the official says.
Ten Saudi students are being held on the base on Saturday while several others are unaccounted for.
US officials had previously told The Associated Press they were investigating possible links to terrorism.
The FBI is examining social media posts and investigating whether he acted alone or was connected to any broader group.
The student – identified as Mohammed Saeed Alshamrani – opened fire in a classroom on Friday morning, killing three people.
The assault, which prompted a massive law enforcement response and saw the base locked down, ended when the attacker was shot dead by police.
Eight people were injured, including two policemen.
Family members on Saturday identified one of the victims as a 23-year-old recent graduate of the US Naval Academy who alerted first responders to where the shooter was even after he had been shot several times.
“Joshua Kaleb Watson saved countless lives today with his own,” Adam Watson wrote on Facebook.
“He died a hero and we are beyond proud but there is a hole in our hearts that can never be filled.”
All of the shooting took place in one classroom and the shooter used a handgun, authorities said.
Weapons are not allowed on the base, which Kinsella said would remain closed until further notice.
Adam Watson said his little brother was able to make it outside the classroom building to tell authorities where the shooter was after being shot “multiple” times. “Those details were invaluable,” he wrote on his Facebook page.
Florida senator Rick Scott issued a scathing statement calling the shooting – the second on a US naval base this week – an act of terrorism “whether this individual was motivated by radical Islam or was simply mentally unstable”.
He added it is “clear that we need to take steps to ensure that any and all foreign nationals are scrutinised and vetted extensively before being embedded with our American men and women in uniform”.
However, a national security expert from the Heritage Foundation warned against making an immediate link to terrorism.
Charles Stimson said it should not be assumed that “because he was a Saudi national in their air force and he murdered our people, that he is a terrorist”.
The gunman was a member of the Saudi military who was in aviation training at the base.
During a news conference on Friday night, the FBI declined to confirm the student’s identity and would not comment on his possible motivations.
US President Donald Trump tweeted his condolences to the families of the victims and noted that he had received a phone call from Saudi King Salman.
He said the king told him that “this person in no way shape or form represents the feelings of the Saudi people.”
The Saudi government offered condolences to the victims and their families and said it would provide “full support” to US authorities.
On Wednesday, a sailor whose submarine was docked at Pearl Harbor in Hawaii, opened fire on three civilian employees at the US base, killing two before taking his own life.