Authorities said they are still unsure what brought the SUV into the path of the truck and why so many people were inside of it. Watson, who heads the agency’s border division, said the scene was “chaotic” when fire crews and law enforcement agents arrived about 10 minutes after the crash; it was not expected to be cleared until late evening because of the ongoing investigation. By late afternoon, the CHP was still working with the coroner’s office to identify passengers. Advertisement At least 10 of the dead were Mexican nationals, said Roberto Velasco Álvarez, who heads the North America Department for the Mexican foreign ministry.