The FBI has arrested a New Mexico man who allegedly illegally detained immigrants crossing the border under the guise of working for the United States Border Patrol.

Larry Mitchell Hopkins runs The United Constitutional Patriots (UCP), an armed border militia group that spreads far-right conspiracies and rounds up asylum seekers on the border.

The FBI arrested Hopkins Saturday on charges of possessing firearms and ammunition as a convicted felon. Recent video footage released by UCP shows two members holding what appear to be semi-automatic rifles near immigrants, many of them children.

The group also peddles conspiracy theories and produces a radio show where members spread information about QAnon, and accuse migrants of associating with ISIS.

Hopkins has also claimed to work with Border Patrol and that president Trump has personally asked him about ‘Muslim immigration.’

UCP is only one of several vigilante groups patrolling the southern border with guns.

New Mexico Attorney General Hector Balderas issued a statement on Saturday, praising the FBI over Hopkins' arrest.

“This is a dangerous felon who should not have weapons around children and families,” Balderas wrote in a statement. “Today's arrest by the FBI indicates clearly that the rule of law should be in the hands of trained law enforcement officials, not armed vigilantes.”

Hopkins is expected to have an initial appearance in U.S. District Court in Las Cruces, New Mexico on Monday.