SILVER SPRING, Md. (AP) — A self-professed white supremacist was wearing a GPS-enabled monitoring device when he joined the crowd of Trump supporters who stormed the U.S. Capitol this month, according to a court filing accompanying his arrest.

Investigators used the monitoring device to retrace Bryan Betancur’s movements on the day of the deadly insurrection. He was wearing the device under the terms of his probation in Maryland after a burglary conviction. His probation officer called the FBI to report that Betancur had claimed to have been inside the Capitol building with rioters and said he was tear gassed during the siege.

Betancur, who was arrested Sunday in Maryland on charges related to the riots, told investigators that has been a member of several white supremacist groups and has expressed a desire to be a “lone wolf killer,” an FBI agent wrote in an affidavit.

Betancur also has expressed support for James Fields, the Ohio man convicted of murder for killing a woman when he plowed his car into a crowd of counterprotesters at a white nationalist rally in Charlottesville, Virginia, in August 2017, according to the affidavit.

“Betancur has stated he wanted to run people over with a vehicle and kill people in a church,” the agent wrote. “Betancur subsequently stated that he had changed his mind about hurting people.”

Betancur, who lived in Silver Spring, Maryland, before the riots, was arrested on charges including engaging in unlawful activities on Capitol grounds, disorderly conduct and engaging in disorderly or disruptive conduct in any restricted building or grounds.

It wasn’t immediately clear if Betancur has an attorney.

An informant provided the FBI agent with screenshots of social media accounts that Betancur apparently used under the names Bryan Clooney and Maximo Clooney. One image shows him standing on scaffolding on the west side of the Capitol building and holding the corner of a Confederate battle flag. Another image shows him wearing a T-shirt associated with the Proud Boys, a far-right extremist group, according to the agent.