A male passenger died at the scene. Twenty others were hurt, including Emelia Policarpio, 16, of Tepetiscal, Mexico, who reportedly suffered a broken neck, according to the California Highway Patrol.
The identity of the man who died was unavailable. County Coroner Investigator Gary Hayes speculated the man died of a crushed skull.
There were reports that three people fled the scene before the U.S. Border Patrol was flagged down by one of the accident victims.
The driver of the Bronco was thought to be among those who fled, and Hayes said the driver likely was a smuggler.
Consulate authorities said the majority of those taken to El Centro Regional Medical Center and Pioneers Memorial Hospital in Brawley late Thursday and early Friday were released shortly after their arrival.
Authorities said they were unsure of the custody status of those who were released.
Later Friday there were reports that three members of the group remained hospitalized in Pioneers, two remained in El Centro Regional and two had been taken to hospitals in San Diego.
Along with Policarpio, the names of the injured are: Omar Gomez Rodriguez, Maria Gomez, Emilio Rivera, Aristeo Urbina, Patricia Aravejo, Jose Alfredo Armenta-Fiero, Blanca Corona, Salvador Urbina, Mario Alberto Gutierrez, Isaias Reyes Policarpio, Xumara Vanessa Jimenez, Gerardo Martinez, Carmen Flores, Maria Breton Cabrera, Jose Pina, Claudio Martinez, Aurelio Vallalobos, Alva Luz Arevalo and Victoria Rosas.
Staff Writer Darren Simon can be reached at 337-4082.