Four years ago, an unlikely group of men unofficially joined the retinue of U.S. Border Patrol agents and customs inspectors that carefully watched thousands of cars and pedestrians stream across the Bridge of the Americas during the morning rush hour.

They did not belong to any of the law enforcement agencies tasked with screening traffic at the port, but instead carried on with their peculiar surveillance effort from the Chamizal National Memorial just steps away from the bridge.

Read the whole story at El Paso Times