At 7:10 p.m. on February 4, 1974, Senior Patrol Agent Edwin C. Dennis was in a van driven by Border Patrol Agent Richard Marroguin with one alien in custody. They were enroute from Ysleta to El Paso, Texas, on the border highway. They were traveling without lights when the vehicle struck some rocks that had been left by a construction crew. The vehicle turned over and Dennis was thrown out of the van and it rolled over him, crushing the upper part of his body. The other occupants in the vehicle were shaken up but not seriously injured.