Thirteen people killed in one of the deadliest border crashes on record were among more than 40 migrants who entered the U.S. through a hole cut into Southern California’s border fence with Mexico, the Border Patrol said Wednesday.

Surveillance video showed a Ford Expedition and Chevrolet Suburban drive through the opening early Tuesday, Gregory Bovino, the Border Patrol’s El Centro sector chief, told The Associated Press. It is believed they were part of a migrant smuggling operation.

The Suburban carried 19 people, and it caught fire for unknown reasons on a nearby interstate after entering the U.S. All escaped the vehicle and were taken into custody by Border Patrol agents.