The fatal shooting carried out by a Saudi Arabian Air Force officer who was conducting a flight training program for foreigners at the Pensacola military base “was an act of terrorism,” Attorney General William Barr said at a press conference on Monday, Jan. 13.

According to Barr, 21-year-old 2nd Lt. Mohammad Alshamrani was shot during the Dec. 6 attack on the Florida naval air base, where he shot and killed three U.S. sailors and seriously wounded eight others.

During the course of the investigation, the prosecution discovered that the “jihadist ideology” terrorist had posted anti-American and anti-Israeli messages on social networks, and obtained judicial authorization to investigate the Saudis’ cellphones.

FBI general counsel Dana Boente sent a letter to Apple requesting its help on the matter, calling it “a high priority national security issue,” given that they were unable to access the gunman’s two devices, an iPhone 7 and an iPhone 5, which are blocked and encrypted.

Apple’s controversial refusal

“When the FBI requested information from us relating to this case a month ago we gave them all of the data in our possession and we will continue to support them with the data we have available,” Apple reported according to ABC News, refusing to provide the access codes.

In a similar case, in 2016, the Justice Department decided—after exhausting all other avenues—to take Apple to court for refusing to unlock the phone of the San Bernardino mass murderer, CNN reported.

“It is very important for us to know with whom and about what the shooter was communicating before he died,” Barr said, according to NPR. “We have asked Apple for their help in unlocking the shooter’s phones. So far, Apple has not given any substantive assistance,” he concluded.

Notably, Alshamrani, before opening fire on the base, hosted a party where he watched videos of mass shootings with others, described by The Associated Press.

Meanwhile, Washington decided to send 21 Saudi military students from the training program back home, of whom 15 “had reviewed or had contact with child pornography” and  17 possessed jihadi or anti-American material, Fox reported.

President Donald Trump called for a review of the program for international airmen in order to neutralize such domestic threats.