A Denver-area teenager was charged Monday with trying to help terrorists after he allegedly planned to travel to the Middle East in order to become a soldier for the Islamic State terrorist group.

The defendant, Humzah Mashkoor, 18, of Westminster, Colorado, was charged in a criminal complaint filed in U.S. District Court in Colorado with knowingly providing or attempting or conspiring to provide material support to a foreign terrorist organization.

An FBI agent’s narrative included in the criminal complaint alleges Mashkoor, born in the United States but raised in part in his family’s native Afghanistan, desperately wanted to return to fight for the Islamic State group, better known as ISIS.

FBI agents arrested him Monday at Denver International Airport as he attempted to fly to the United Arab Emirates as part of the alleged plan to end up back in Afghanistan and meet with ISIS “brothers,” according to the complaint.

The bureau became aware of Mashkoor in 2021 when a social media company alerted it to a post by the defendant that expressed support for the terrorist group, the court filing states.

The federally designated Foreign Terrorist Organization based in Iraq and Syria is a jihadist group — militants who pine for a holy war that would leave their school of Islam victorious — that has undertaken or inspired terrorist attacks resulting in thousands of casualties around the world, according to the office of the Director of National Intelligence.

In July 2022, police in the city of Thornton, about 10 miles north of Denver, alleged Mashkoor assaulted a relative, who told officers the teenager said he “wanted to kill people and cut their heads off,” according to the court document.

Another relative allegedly told police Mashkoor “struggled from mental illness and had high-functioning autism.”

In September 2022, he started communicating online with an FBI agent posing as an ISIS supporter, the complaint said.

From then through Monday of this year, that agent and others posing as ISIS supporters communicated with the teen, documenting his alleged intentions, the filing states.

At one point, Mashkoor communicated with two real ISIS supporters with alleged real-world terrorist ties, including one convicted for terror-related activity in a foreign country, the complaint alleged.

He pondered staying in the United States to work for ISIS to help carry out a domestic attack, according to the complaint. The idea, suggested by an online ISIS contact, “was something I considered as a last effort,” Mashkoor is quoted in the complaint as saying.

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The teenager also considered the possibility he would be immediately be deployed as a suicide bomber upon reaching ISIS militants in the Middle East, the document states.

He pondered whether to go to Syria instead of Afghanistan, but fretted that the had no contacts there, prosecutors said. He also fretted about finding a bride, which seemed integral to his alleged plan, they said.

The defendant thought about sending money to ISIS by converting it to cryptocurrency, but he had difficulty determining how to do so without being traced, according to the complaint. After turning 18, he asked for a relative’s help in removing their name from his bank account so he could move forward with the cryptocurrency plan without their knowledge, it stated.

When one of the covert agents asked if the relative knew what he was trying to do, Mashkoor said it was likely. “She cried a little after I changed the stuff and then she said, ‘You are not allowed to send money to any bad people,'” the complaint quotes the defendant as saying.

Mashkoor said he suffered from depression, and he couldn’t wait to leave the United States, the agents in touch with him said, according to the court filing.

“I can’t stand another day of humiliation living in dar ul kuf,” the defendant is quoted as saying. The term “dar ul kuf” refers to the portion of the world that doesn’t follow Islam.

The trip to United Arab Emirates was postponed by more than a week because the Mashkoor contracted Covid, the filing states.

On Monday, just after 9:30 a.m., FBI agents arrested Mashkoor at Denver International Airport. Later, they searched his home in Westminster, about 20 miles north of Denver, and found journal entries, according to the complaint.

In prosecutors’ words, the teenager wrote that “he has felt isolated since he was young, but then discovered that there were ‘others like’ him.”

Mashkoor is also quoted as stating his goals in a journal entry: “Victory over my enemies, or martyrdom.”

Mashkoor made an appearance Friday in federal court. It wasn’t immediately clear if he had a lawyer, and the federal public defender in Colorado did not immediately respond to a request for comment.