Officials are investigating the motive behind a shooting at Naval Air Station Pensacola early Friday by a Saudi aviator in training, who purportedly authored a series of tweets expressing hatred of the United States.
The shooter pulled out a handgun in a classroom at the Florida Navy base and opened fire, killing three people and injuring eight others before a deputy fatally shot him, authorities said.
While the FBI has not yet confirmed whether or not it's investigating terrorism as a motive for the attack, Pensacola's congressional representatives have characterized the incident as an "act or terrorism."
The shooting happened just two days after a U.S. Navy sailor shot three people and then killed himself at Pearl Harbor.
Navy Adm. Mike Gilday, chief of naval operations, said it has been "a devastating week for our Navy family."
Here's what we know.
Who was the NAS Pensacola shooter?
The shooter was identified as a member of the Saudi military, according to a Defense official who spoke to USA TODAY on condition of anonymity.
Why was a Saudi national at NAS Pensacola?
He was one of 852 Saudi nationals in a training program that invites the "best of the best" from foreign allies' militaries to receive training in the U.S. He began his three-year course in August 2017 with English, basic aviation and initial pilot training.
About 5,180 foreign students from 153 countries in the United States participate in the program. Many of those students operate U.S. military hardware that foreign governments buy from the United States. Saudi Arabia is the world's largest customer for arms, and many of those are American made.
FBI investigating motive, tweets
Hours before the shooting, tweets purportedly written by the suspect railed against the United States for its support of Israel and for stationing troops at bases in Saudi Arabia.
The tweets are addressed to "O American people" and outline what the author said is a hatred of the United States for crimes against Muslims, including the detention of suspects in Guantanamo Bay.
'O American people': FBI investigating tweets purportedly from suspect
The FBI is working to confirm that the tweets came from the Saudi military trainee and has not yet confirmed whether or not it's investigating terrorism as a motive for the attack.
Also investigating are the Bureau of Alcohol, Tobacco, Firearms and Explosives; the Department of Defense and other national, state and federal agencies.
What does this mean for US-Saudi relations?
The U.S. has long had a robust training program for Saudis, providing assistance in the U.S. and in the kingdom. The shooting, however, shined a spotlight on the two countries' sometimes rocky relationship.
President Donald Trump, who spoke with King Salman of Saudi Arabia shortly after the shooting, said the monarch called the attack "barbaric."
"Obviously, the government of Saudi Arabia needs to make things better for these victims," Florida Gov. Ron DeSantis said in a press conference. "They're going to owe a debt here."
More than a year ago, journalist Jamal Khashoggi, a U.S. resident and critic of Saudi Arabia's government, disappeared inside the Saudi Consulate in Istanbul. His remains have yet to be found, but a United Nations report concluded that there was "credible evidence" that Crown Prince Mohammed bin Salman masterminded the killing.
'Serious failure' in vetting foreign military students
Pensacola's congressional representatives are calling for a better vetting process for training foreign military members on U.S. bases.
U.S. Sen. Rick Scott, R-Fla., on Friday called for a full review of the programs that train foreign nationals.
"There is no reason we should be providing state-of-the-art military training to people who wish us harm," Scott said in a press release. "It's clear that we need to take steps to ensure that any and all foreign nationals are scrutinized and vetted extensively before being embedded with our American men and women in uniform."
I'm very concerned that the shooter in Pensacola was a foreign national training on a US base.
Today, I'm calling for a full review of the US military programs to train foreign nationals on American soil. We shouldn't be providing military training to people who wish us harm. pic.twitter.com/JkypdikYI9
- Rick Scott (@SenRickScott) December 6, 2019
U.S. Rep. Matt Gaetz, R-Fla., called for "extreme vetting" in the programs.
"This event demonstrates a serious failure in the vetting process and in the way in which we invite these people to our community," Gaetz said on Twitter.
We're learning a Saudi Arabian military member in Pensacola committed these murders.
I'm working with the @DeptofDefense, @StateDept, and @DHSgov to ensure there's extreme vetting for people who come to our country and train on our bases. pic.twitter.com/LUhSE6UAHO
- Rep. Matt Gaetz (@RepMattGaetz) December 6, 2019
Congressional representatives cite 'terrorism'
"Whether this individual was motivated by radical Islam or was simply mentally unstable, this was an act of terrorism," Scott said.
Gaetz also characterized the shooting as an "act of terrorism."
"This was not a murder. This was an act of terrorism," Gaetz said in a TV interview.
This was not a murder. This was an act of terrorism. pic.twitter.com/AJfTQOOE68
- Rep. Matt Gaetz (@RepMattGaetz) December 6, 2019
How did the shooting unfold?
The shooting began around 6:30 a.m. CT and the suspect was stopped by Escambia County sheriff's deputies, who arrived on scene in less than five minutes, Sheriff David Morgan said. One of the deputies fatally shot the gunman, he said.
Eight patients, including two deputies, were taken to nearby Baptist Hospital. One of the victims died at the hospital, and two died on the base. The shooter also died on the base.
One officer was shot in arm and treated at the hospital. Another was shot in the knee and underwent surgery. On Saturday, one had been released from the hospital, and the other remained in the hospital recovering.
NAS Pensacola shooting: How sheriff's deputies responded
Who are the shooting victims?
The names of the victims will not be released until the next of kin have been notified, authorities said.
Family members, however, identified Joshua Kaleb Watson, 23, a recent graduate of the U.S. Naval Academy, as one of the victims.
"Joshua Kaleb Watson saved countless lives today with his own," Joshua's brother, Adam, wrote on Facebook late Friday. "After being shot multiple times he made it outside and told the first response team where the shooter was and those details were invaluable."
Shooting at Navy base: Shooting victim 'saved countless lives with his own'
What weapon did the gunman use?
An official who was not authorized to speak publicly told USA TODAY that the Saudi national did not use his military-issued service weapon.
He used a handgun, authorities said.
'The loneliest club': For survivors caught in endless loop of mass shootings, time doesn't always heal
What is NAS Pensacola?
Located in the far western Panhandle, the Pensacola base employs more than 16,000 military and 7,400 civilian personnel. The base is home of the Blue Angels, the Navy's Flight Demonstration Squadron, and the National Naval Aviation Museum.
USA TODAY's Grace Hauck contributed from Chicago and Doug Stanglin and Kevin Johnson from Washington; Annie Blanks, Jim Little and Kevin Robinson reported from Pensacola for the Pensacola News Journal.
This article originally appeared on USA TODAY: Pensacola shooting: What we know about tweets, Saudi national, motive