There is nothing patriotic about holding toddlers at gunpoint. It’s hard to believe that this even needs to be said. But that’s exactly what an armed group of vigilantes calling themselves the “United Constitutional Patriots” … has been doing along the southern border of New Mexico for the past several months. This group, which until recently was squatting on a remote parcel of railroad-owned land near Sunland Park, filming themselves detaining groups of migrants, mostly families with young children, and holding them until Border Patrol arrived on the scene.

The self-shot footage is disturbing. The UCP members are clad in military-style camouflage, wear masks concealing their identities, and many are armed with AR-15-style semi-automatic rifles with high-capacity magazines. The families are huddled together in the darkness, ordered to sit or kneel in the desert sand under implied threat of violence. In one of the clips … a UCP vigilante trains his flashlight on a pair of migrant men sleeping on the ground and muses, “The only problem is if we shoot on the hill it will be an international crisis. … It would save some time though, wouldn’t it?”

This kind of vigilantism is not only a disgusting display of xenophobia, it’s a tragedy waiting to happen. It’s easy to see how quickly the situation could devolve into a bloodbath. Should one of these untrained and heavily armed extremists perceive a threat – maybe in the darkness they mistake a cellphone in a migrant’s hand for a gun – and open fire into the densely packed crowd, how many innocent lives might be lost?

One of the most disturbing aspects of UCP’s illegal detention of migrants on the border is that they appear to have been operating with the full knowledge and tacit approval of U.S. Border Patrol. Indeed, every indication appears to show that U.S. Border Patrol agents actively coordinated with the group’s illegal activities.

Though the FBI recently arrested the group’s leader, Larry Mitchell Hopkins, on unrelated firearms charges after the ACLU of New Mexico wrote a letter demanding investigation of the group’s activities, little else appears to have been done aside from local police evicting the group from railroad property. Ample video evidence exists depicting UCP members unlawfully detaining families at gunpoint and impersonating federal law enforcement officers by self-identifying to groups of migrants as “policia” or “U.S. Border Patrol.” Yet, U.S. Border Patrol has so far responded with little more than a shrug, and the U.S. Attorney’s Office has provided little indication it intends to take action beyond Hopkins’ arrest.

We cannot tolerate this kind of lawless thuggery in our state. Just as we would never stand for a private citizen pulling over another driver at gunpoint for speeding, we cannot allow armed bands of civilians to enforce our federal immigration laws. Indeed, vigilantism is responsible for some of the darkest and most evil deeds in our history. One need to look no further than the KKK lynch mobs, the torching of Chinese neighborhoods in LA, and Native American massacres to understand where tolerance of vigilantism leads.

While we do not contest the right of groups like UCP to conduct legal activities on public lands, the unauthorized detention of migrants cannot continue. The ACLU of New Mexico joins Sens. (Tom) Udall and (Martin) Heinrich in demanding authorities take this threat seriously and investigate potential illegal activities committed by UCP in order to prevent this kind of dangerous and lawless behavior from continuing on our border. The enforcement of federal immigration law belongs solely in the hands of trained law enforcement professionals – not armed vigilantes.

This op-ed was originally published in the Albuquerque Journal.