The American Civil Liberties Union denounced the actions of a right-wing militia group that’s detaining migrant families before turning them over to Border Patrol agents, The New York Times reports. Members of the group United Constitutional Patriots apprehended about 200 asylum-seeking migrants this week near Sunland Park, New Mexico—activity that was reportedly filmed and posted on social media. The group, which operates near the border, has also allegedly held migrants at gunpoint. “We cannot allow racist and armed vigilantes to kidnap and detain people seeking asylum,” ACLU lawyers María Martínez Sánchez and Kirsten Greer Love wrote in a letter Thursday that called for an investigation by New Mexico’s governor and attorney general. Hector Balderas, New Mexico’s attorney general, appeared to agree. “These individuals should not attempt to exercise authority reserved for law enforcement,” he said in a statement.