FILE - In this March 1, 2017 file photo, an Iraqi soldier inspects a recently-discovered train tunnel, adorned with an Islamic…
FILE - In this March 1, 2017 photo, an Iraqi soldier inspects a tunnel, adorned with an Islamic State group flag.

SEATTLE, WASHINGTON - A 20-year-old Seattle man is facing a terrorism-related charge after he was arrested while trying to board a flight to join the Islamic State (IS) group, the U.S. Justice Department said Tuesday.

Elvin Hunter Bgorn Williams was arrested Friday at Seattle-Tacoma International Airport as he checked in for a flight to Cairo, Egypt, according to a criminal complaint unsealed Tuesday in U.S. District Court in Seattle.

The complaint said members of a Seattle-area mosque who had been trying to de-radicalize Williams told the FBI that he continued to espouse violence and extremism.

Williams made an initial video appearance in court Tuesday on a charge of providing material support to a terrorist organization. Corey Endo, an assistant federal public defender, was appointed to represent Williams, who was ordered detained pending further proceedings. Endo declined to comment after the hearing.

The complaint described Williams as "self-radicalized" and said he first came to the FBI's attention when he was 16. That's when administrators at his high school reported that he was telling others he wanted to join IS and that the fatal terrorist attack on an Ariana Grande concert in England was justified by the way the singer dressed.

At the time, his mother told the FBI that Williams had been kicked off social media for his pro-IS posts and that she cut off the internet service at their home to keep him from accessing extremist websites, the complaint said.

Last November, a member of the mosque, which is not identified in court papers, contacted the agency to report concerns about Williams, FBI Special Agent David Narrance wrote in the complaint. As an act of charity, the mosque had been looking after him in an attempt to de-radicalize him — helping to give him a place to live, food and tuition for a semester of college.

Members of the mosque also gave him a cellphone and a laptop in hope that the items would help him find a job, the complaint said. But they also made clear he would have to abandon IS if he wanted help.

A member of the mosque, after seeing Williams using the phone to watch IS-related videos and engage in extremist online chats, demanded the phone back, Narrance wrote. Members of the mosque reviewed the phone and were disturbed by what they found: graphically violent videos, including beheadings by IS militants, and bomb-making instructions.

The FBI opened an investigation and enlisted the help of several confidential informants, including some who messaged with Williams about his plans and others who posed as IS recruiters. In messages cited in the complaint, Williams discussed his willingness to become a martyr, his preference for fighting in the desert over the jungle, his fervent wish to behead someone — and his concern that he would be arrested at the airport.

He spent much of this year working and saving up for travel expenses, the complaint said. He received his passport on May 6.

"This defendant proved persistent in his efforts to join ISIS — speaking with enthusiasm about acts of horrific bloodshed in the Middle East and here at home," Tessa Gorman, acting U.S. attorney for western Washington state, said in a news release. "I want to commend those citizens who contacted law enforcement — including his family and faith community — expressing concerns about the defendant's radicalization."

When he was arrested, the complaint said, Williams agreed to speak with investigators. The complaint quotes him as saying that he intended to become an "executioner" or a "machine-gunner."

"It doesn't matter what you guys do to me. I get rewarded for it," Williams said, according to the complaint. He added: "I want to die. We love our deaths more than you love your lives."