The FBI arrested the leader of a militia that has been detaining migrant families at the border

Larry Mitchell Hopkins, 69, a leader of the United Constitutional Patriots, was arrested on charges of being a felon in possession of firearms and ammunition, the FBI said.
The group's actions has prompted outrage in recent days, after a video showed a group of nearly 300 migrants sitting on the ground near Sunland Park, New Mexico, as members of the group shone flashlights in their faces.
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The FBI has arrested the leader of a militia group that was recently seen on videos detaining migrant families at the US-Mexico border, the agency announced Saturday .

Larry Mitchell Hopkins, 69, a leader of the United Constitutional Patriots, was arrested on charges of being a felon in possession of firearms and ammunition, the FBI tweeted. He also went by the alias Johnny Horton Jr., and will appear in a New Mexico court on Monday.

"This is a dangerous felon who should not have weapons around children and families," New Mexico's attorney general, Hector Balderas, said 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."

The group's actions has prompted outrage in recent days, after a video showed a group of nearly 300 migrants sitting on the ground near Sunland Park, New Mexico, as members of the United Constitutional Patriots shines flashlights in their faces.

A spokesman for the group, Jim Benvie, told The New York Times the group's actions were legal, saying it was akin to "a verbal citizen's arrest." He added that the group will stay at the border until President Donald Trump's wall is built, or until America's asylum laws are changed.

"We're just here to support the Border Patrol and show the public the reality of the border," he said.

The news comes amid a surge of Central American migrant families seeking asylum in the US and infuriating the Trump administration. More than 100,000 migrants crossed the border last month, and that number is expected to rise in April.

united constitutional patriots AFP/Paul Ratje via Getty Images

Rights groups like the American Civil Liberties Union have denounced the group, urging New Mexico's governor and attorney general in a letter to immediately investigate the group's "atrocious and unlawful conduct."

"The vigilante members of the organization are not police or law enforcement and they have no authority under New Mexico or federal law to detain or arrest migrants in the United States," two ACLU lawyers said in the letter. "The Trump administration's vile racism has emboldened white nationalists and fascists to flagrantly violate the law."

Customs and Border Protection also said in a statement Friday it doesn't endorse or condone private groups taking "matters into their own hands," and that community members who witness or suspect "illegal cross-border activity" can call Border Patrol's tip line.

"Interference by civilians in law enforcement matters could have public safety and legal consequences for all parties involved," the agency tweeted .