For the first time, the FBI has charged a law enforcement officer in the United States with attempting to provide material support to the Islamic State.

The accused, a 36-year-old transit police officer in Washington, D.C. named Nicholas Young, was arrested by the FBI on Wednesday at the Metropolitan Police Headquarters, according to the Washington Post.

Young was caught in an FBI sting operation, in which an undercover operative for the Joint Terrorism Task Force convinced him to provide “codes for mobile messaging cards that Young believed would be used by Islamic State fighters overseas to communicate,” as the Washington Post reports.

NBC News more specifically details that Young attempted to buy 22 mobile messaging gift cards for ISIS. He had a total of 20 meetings with an FBI informant who was posing as an Islamic State fighter.

ABC News reports that Metro police “initiated” the probe into Young, who has been under investigation by the FBI for “several years,” as outlined by Washington Metropolitan Area Transit Authority CEO Paul Wiedefeld in a memo to his colleagues on Wednesday morning.

Wiedefeld also notified his colleagues that Young was fired, “effective immediately.”

“Since I received my first briefing on this matter, [Metro Transit Police] Chief [Ronald] Pavlik and I have worked hand-in-glove with the FBI in the interest of public safety and to ensure that this individual would be brought to justice,” Wiedefeld said in a statement quoted by Fox News.

Young has been working for the D.C. Metro police since 2003 despite being monitored by the FBI since 2010, and traveling to Libya twice in 2011 to fight alongside rebel forces against the regime of Moammar Qaddafi. NBC quotes prosecutors describing him as “a longtime supporter of Islamic extremism” who also has “Nazi sympathies.”

It seems incredibly risky to have left him in his position for so long, but officials assured the media he “did not pose any threat to the Metro system,” as the Associated Press puts it.

Young is scheduled to make his first court appearance today, and could face up to 20 years in prison if convicted.