The Sacramento County Coroner's Office has released the name of one of the four people who died in a crash on Interstate 5 south of Sacramento on Sunday.
She was identified as 50-year-old Kulwant Kaur Gill.
A California Highway Patrol accident investigation team has begun work to find out what caused the crash, which also left at least seven people injured.
"We don't have a cause to release as yet," said CHP spokesman Officer Michael Bradley.
"Initially, we are investigating an unsafe turning movement that caused the car to leave the roadway."
A 2004 Ford Expedition crossed over the median north of Hood Franklin Road and entered the northbound lanes of I-5 at about 3:30 p.m., authorities said.
There, the SUV hit a 2012 Honda Accord and a 1997 Toyota Rav4, which was towing a boat.
Four people died at the scene. Seven people were transported to area hospitals, four with critical injuries.
Northbound I-5 was closed for about eight hours so that the CHP could begin its look into the crash.
The Multidisciplinary Accident Investigation Team planned to conduct an in-depth analysis of the collision.
CBS 13 reported that tire tread was missing from the Expedition, which could indicate tire failure as a possible cause.
"We are going to be conducting an investigation on the Expedition to determine if there was a mechanical problem that caused it to leave the roadway," Bradley said.
The Expedition had nine people inside. Three were killed and six injured.
Among the fatalities was the driver, tentatively described as in his 50s from Berkeley, according to the CHP. Also killed in the Expedition was a 70-year-old woman from Berkeley, and Gill, who is listed by the CHP as being from Lathrop.
Those injured in the Expedition included two people from Lathrop: a woman in her 40s and a 17-year-old boy. Also injured in the SUV were four people from Berkeley: three women, ages 18, 19 and 23, and a 20-year-old man.
Their injuries ranged from broken wrists and ribs to major trauma.
The fourth person to die in the crash was the driver of the Honda Accord, a man in his 50s. A passenger in his car suffered major injuries.
The driver of the Toyota Rav4 suffered a minor injury.