By CBSLA Staff

IMPERIAL (CBSLA/AP) — Authorities say a human smuggling investigation is underway after 13 people were killed Tuesday morning when an SUV carrying over two-dozen people collided with a big rig on a Southern California highway in Imperial County near the U.S.-Mexico border.

Twelve people were found dead when first responders reached the highway, which winds through fields in the agricultural southeastern corner of California. Another person died at a hospital, California Highway Patrol Chief Omar Watson said.

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Authorities do not yet know if the driver of the 1997 Ford Expedition, who died in the crash, had stopped at a stop sign before crossing into the path of the big rig around 6:15 a.m., Watson said. The big rig hit the left side of the SUV, which appeared to have been pushed off the road that’s about 100 miles east of San Diego.

(credit: CBS)

“It would be premature of me to speculate what happened at this collision,” Watson said. “We owe it to the families of those that were killed, as well as the public, to conduct a complete and thorough investigation to determine exactly what happened.”

A Homeland Security spokesperson released this statement Tuesday evening: “Special Agents from Homeland Security Investigations San Diego responded to the scene of today’s fatal crash in El Centro, California, and have initiated a human smuggling investigation. The investigation is ongoing and no further details are available at this time.”

A U.S. Customs and Border Protection official, who requested to remain anonymous, confirmed that there was a breach in the border wall near the crash site which was being investigated in connection with the crash.

The National Transportation Safety Board said in a tweet that its investigators would also be looking into the crash.

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A Ford Expedition typically seats eight people legally. The CHP did not immediately know why so many occupants had been crammed into the SUV. The driver was a 22-year-old man from Mexicali, a city just over the Mexico border.

In a news briefing, Judy Cruz, the managing director for the El Centro Regional Medical Center’s emergency department, said that seven people were brought to El Centro Regional, one of whom died on arrival. Another three people were airlifted to other hospitals and two were taken to Pioneers Memorial Hospital in the town of Brawley.

Cruz initially reported that at least 15 people had died in the wreck, but that number was later downgraded slightly.

The wreck occurred about 15 miles north of the U.S.-Mexico border and 15 miles east of El Centro.

Authorities are working with the Mexican consulate to identify the victims, who range in age from 20 to 55. Among the injured, the youngest is 16. Watson said some of the SUV’s occupants did not speak English and translators are helping the CHP. It’s typical for people to cross the border daily.

“It was an unusual number of people in an SUV, but we don’t know who they were,” Mora said, adding that they could have been farmworkers.

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(Copyright 2021 CBS Corp. The Associated Press contributed to this report.)