PALO ALTO -- It was supposed to be a way for the San Bruno family to have a night of fun together, shopping for the gifts they would take with them to India for the eldest daughter's wedding in January. But just before sunrise on Black Friday, the shop-till-you-drop marathon turned deadly, as the family's golden SUV slammed into the back of a California Highway Patrol car on Highway 101, killing the bride-to-be, 24-year-old Nisha Tandel, instantly.

Two more of the family's four daughters were critically injured when the Lexus flipped over, according to relatives, and the condition of one was thought to be grave. Both of the parents were also injured, and the CHP officer -- who had pulled off the highway to help a pickup truck driver change a flat tire near the Oregon Expressway -- sustained minor injuries.

Late Friday, the CHP identified the family members being treated at Stanford Hospital as the mother Yogita Tandel, 34, and daughter Sheetal Tandel, 20. The father, Arvind Tandel, 48, and daughter Payal Tandel, 22, were also in the car along with a minor whose name was not released.

Almost home

When their SUV inexplicably went off the highway, the Tandels were only 23 miles from their San Bruno home, which the family kept so tidy that in 2003 it won an award from the city's Beautification Task Force. The collision was reported at 6:49 a.m., in the pre-dawn dusk that meteorologists refer to as "civil twilight." The CHP, which closed most lanes on northbound 101 for six hours Friday as it investigated the accident, didn't rule out falling asleep at the wheel as its possible cause. "It's unclear why the (driver) drifted off the roadway," CHP Sgt. Diana McDermott said.

Nisha Tandel and one of her sisters were thrown from the vehicle. It was unclear from the CHP's preliminary investigation whether either was wearing a seat belt. The father, mother and two sisters who remained inside the vehicle were wearing seat belts, officer Amelia Jack said. Nisha Tandel died at the scene. The dead woman was identified Friday afternoon by her granduncle, Kantilal Gandhi, who gathered with family at Stanford Hospital.

So much grief

Traffic was backed up for miles while CHP investigators shut down several lanes of the freeway until 1 p.m. The crash site was littered with debris, and among the twisted metal and broken glass, there were ripped and tattered shopping bags.

Outside the emergency room at Stanford Hospital, relatives and members of the family's San Bruno community congregated in mourning. Some looked close to fainting and sobbed uncontrollably, while others went in and out of the hospital, their faces ashen with grief.

At the Tandel family home, someone who answered the phone asked only for privacy.

Eric Kurhi contributed to this report. Contact Robert Salonga at 408-920-5002. Follow him at Twitter.com/robertsalonga.