The Saudi airman who killed three at a naval training center in Pensacola filed a complaint earlier this year against an instructor who called him 'Porn Stash.'

Saudi Royal Air Force Second Lieutenant Mohammed Saeed al-Shamrani lodged a complaint in April against the instructor who gave him the nickname, in reference to his mustache, in front of 10 other students, according to The New York Times.

'I was infuriated as to why he would say that in front of the class,' al-Shamrani wrote in his complaint.

The FBI declined to comment on the incident. Investigators do not believe that the incident had any connection to Friday's shooting, the Times reported.

But they are coming under increasing pressure to deliver answers on the motive behind the shooting at the U.S. Navy base on Friday morning.

The bureau said Sunday it will be investigated as a potential act of terrorism as authorities explore whether the gunman's sickening actions were spurred by a radical ideology.

He had visited the 9/11 memorial in New York just two days before shooting where he met up with at least five other Saudi airmen and was able to buy the Glock 9mm pistol he used in the shooting legally in Florida.

Months before Friday's shooting at Naval Air Station in Pensacola, Florida, Saudi gunman Mohammed Saeed al-Shamrani (above) lodged a complaint against an instructor who called him 'Porn Stash' - a reference to his mustache resembling that of a pornographic film actor

The above image shows police tape stretching across a street near a building at Naval Air Station Pensacola on Saturday

Special Agent in Charge Rachel Rojas revealed Sunday that investigators have not yet been able to determine the motive.

Florida Governor Ron DeSantis, speaking at a Sunday evening press conference, said he was sure the gunman carried out an act of terrorism. He questioned whether it could have been prevented by better vetting of foreign military officers who train in the United States.

'There is a lot of frustration in our state over this,' DeSantis said. 'You have foreign military personnel coming to our base. They should not be doing that if they hate our country.'

'I'm big supporter of the Second Amendment, but it's so Americans can keep and bear arms, not Saudi Arabians', DeSantis added.

Authorities also believe the shooter authored a series of social media posts in which he talked about U.S. support for Israel and scolded Americans for being anti-Muslim.

After a trip home to Saudi Arabia in February, colleagues say he had become more religious, The New York Times reports.

It emerged as:

Investigators face mounting pressure Monday to deliver answers on the motive

The gunman visited 9/11 memorial in New York just two days before shooting

Key part of the investigation into the shooting now turns to Texas, ABC reports

FBI confirmed Sunday al-Sshamrani had legally purchased the Glock 9mm pistol

Authorities also believe he authored a series of social media posts in which he talked about U.S. support for Israel and scolded Americans for being anti-Muslim

His fellow Saudi students are speaking directly with American investigators

Colleagues say he appeared more religious after a trip home in February

A key part of the investigation has now turned to Texas, ABC reports. Al-Shamrani was first deployed to Lackland AFB, now part of Joint Base San Antonio.

The 'Porn Stash' incident took place at the end of a meteorology class taught by James Day.

Before Day dismissed the students, he asked if anyone had any questions.

He then turned to al-Shamrani and referred to him as 'Porn Stash.'

'Laughing, he continued to ask, 'What? Have you not seen a porn star before?' al-Shamrani wrote in his complaint, which was prepared with the help of two other American trainees.

'After I did not respond, he just let go of the subject.'

Family members and others identified the three dead as Airman Apprentice Cameron Scott Walters, 21, of Richmond Hill, Georgia (left); Airman Mohammed Sameh Haitham, 19, of St. Petersburg, Florida (center); and Joshua Kaleb Watson, a 23-year-old graduate of the US Naval Academy (right)

Members of the Air Force Old Guard Carry team carry the transfer case of Seaman Apprentice Cameron S. Walters at Dover Air Force Base on Sunday

The head of the company that employs Day refused to discuss details of the incident.

Brian Busey, the president of Delaware Resource Group of Oklahoma, said the matter was dealt with in April.

'Appropriate personnel action was taken regarding the incident in question, corrective action was taken, the matter was closed back in April, and we have no further comment, Busey told the Times.

Members of the Air Force Old Guard Carry team carry the transfer case of Seaman Mohammed Haitham on Sunday. Acting Navy Secretary Thomas Modly (center) and Navy Admiral Michael Gilday (right), the chief of naval operations, look on

Door Attendant Staff Sergeant Siannie L. Concepcion closes the door of the transport vehicle carrying the transfer cases of three military members killed

The revelation about the complaint filed by al-Shamrani surfaced on the same day that investigators learned he and other Saudi airmen who were in the US for military training visited the September 11 memorial in New York City just days before the shooting.

AL-SHAMRANI'S DISTURBING TWITTER ACCOUNT AND HIS PRE-SHOOTING 'MANIFESTO' The now-deactivated Twitter account purportedly belonging to Alshamrani included: - A variety of anti-Israel postings and a quote from deceased al-Qaeda leader Osama bin Laden - A lengthy manifesto posted at 4:39am Friday, less than two hours the shooting. The manifesto read in part: 'I'm against evil, and America as a whole has turned into a nation of evil. 'I'm not against you for just being American, I don't hate you because [of] your freedoms, I hate you because every day you [are] supporting, funding and committing crimes not only against Muslims, but also humanity.... Advertisement

Senior law enforcement officials also say that al-Shamrani, 21, made preparations for the shooting by filing paperwork to purchase a gun in April.

The revelations about al-Shamrani's movements are part of efforts by investigators to establish an exact timeline in the weeks leading up to Friday's shooting rampage, according to The Daily Beast.

In the hours leading up to the attack, the shooter appeared to have posted criticism of U.S. wars in the Middle East to social media, saying he hated Americans for 'committing crimes not only against Muslims but also humanity' and for the country's support of Israel.

He also posted a quote from assassinated al Qaeda leader Osama bin Laden, according to SITE Intelligence Group. The shooter's Twitter account was taken down subsequent to the attack.

As of Sunday, investigators have no indication that al-Shamrani was helped by others.

Alshamrani was on the base as part of a U.S. Navy training program designed to foster links with foreign allies. He had started training in the United States in 2017 and had been in the Pensacola area for the past 18 months, authorities said.

Family members and others identified the three dead as Joshua Kaleb Watson, a 23-year-old graduate of the US Naval Academy; Airman Mohammed Sameh Haitham, 19, of St. Petersburg, Florida, who joined the Navy after graduating from high school last year; and Airman Apprentice Cameron Scott Walters, 21, of Richmond Hill, Georgia.