3 missing after 'Hart tribe' family's mysterious crash off cliff

Brake failure, a blown tire and factors such as the weather and road condition are among the factors that will be looked at by investigators trying to determine what caused an SUV carrying a Washington state family to plunge off a California cliff, but authorities might never figure out exactly what happened.

Authorities don't know exactly when or how SUV went over the edge of the Pacific Coast Highway

This March 2016 photo shows the Hart family of Woodland, Wash., at a Bernie Sanders rally in Vancouver, Wash. Authorities in Northern California say they believe eight family members were in a vehicle that plunged off a coastal cliff. (Tristan Fortsch/KATU News/Associated Press)

Brake failure, a blown tire and factors such as the weather and road conditions are among the factors investigators will look at as they try to determine what caused an SUV carrying a Washington state family to plunge off a California cliff, but authorities might never figure out exactly what happened.

Authorities don't know exactly when or how the SUV — which was discovered Monday — went over the 30-metre cliff alongside a spot commonly used by motorists to walk their pets.

They say they have no reason so far to believe it was an intentional crash that claimed the lives of two women and at least three of their six adopted children just days after child welfare authorities tried to contact the family over concerns about the kids' living conditions.

'A lot of unknowns'

But they also said there were no skid marks or signs the driver braked as the GMC Yukon crossed a flat dirt pull-off area about 23 metres wide and went over the edge of the Pacific Coast Highway.

"There are a lot of unknowns on this," Mendocino County Sheriff Tom Allman said. "Several of the questions that have been asked today will never be answered."

This June 2014 photo shows some members of the Hart family at the annual celebration of The Goonies movie in Astoria, Ore. (Thomas Boyd/The Oregonian/Associated Press)

Allman appealed to anyone who might have seen the family of eight to come forward. 

The wreck was discovered by a passing motorist Monday afternoon. The married couple, Jennifer and Sarah Hart, both 38, were found dead inside the SUV, while three of their children — Markis Hart, 19, Jeremiah Hart, 14, and Abigail Hart, 14 — were discovered outside the vehicle. Three other children are missing and presumed dead.

A team on Thursday continued to search the rugged coastline for the three other children, also believed to have been in the SUV: Hannah Hart, 16, Sierra Hart, 12, and Devonte, 15.

The brood was known as the Hart Tribe, a multiracial family who grew their own food, took spontaneous road trips to camp and hike, and travelled to festivals and other events, offering free hugs and promoting unity.

Devonte Hart drew national attention after the black youngster was photographed in tears, hugging a white police officer during a 2014 protest in Portland, Oregon, over the deadly police shooting of a black man in Ferguson, Missouri. Devonte was holding a "Free Hugs" sign.

Black box recorder

Experts say accident reconstruction experts will have information to work with as they study how fast the car was going and other factors.

That model of Yukon was presumably equipped with a black box recorder that would show its speed and use of the brakes, said Marcus Mazza, an engineer and accident-reconstruction expert with Lancaster, Pennsylvania-based Robson Forensic.

A truck drives by the pull-out where the SUV of Jennifer and Sarah Hart was recovered off the Pacific Coast Highway, near Westport, Calif., Wednesday. (Alvin Jornada/The Press Democrat/Associated Press)

Investigators can calculate the SUV's speed based on where it landed and the height of the drop.

"It's basic physics," Mazza said.

Family friend Max Ribner took issue with the notion it was something other than a tragic accident. The couple adopted the six children, many of whom came from "hard backgrounds," he said. "They transformed these kids' lives."

On Thursday, authorities in Washington state also searched the family's home for information. The Clark County Sheriff's Office said deputies were looking for bills, receipts or anything else to shed light on why the family left and other circumstances related to the trip, KGW-TV reported.

Child-welfare investigation

Well before the wreck, Sarah Hart pleaded guilty in 2011 to a domestic assault charge in Douglas County, Minnesota, telling authorities "she let her anger get out of control" while spanking her six-year-old adopted daughter, court records show.

Authorities investigate at the home of Jennifer and Sarah Hart and their six children. (Jim Ryan/The Oregonian/Associated Press)

Then, last week, Bruce and Dana DeKalb, next-door neighbours of the Harts in Woodland, Washington, called state child protective services saying Devonte had been coming over to their house almost every day for a week, asking for food.

Dana DeKalb said Devonte told her his parents were "punishing them by withholding food." The boy asked her to leave food in a box by the fence for him, she said.

Social service authorities opened an investigation, and a state caseworker went to the house last Friday but didn't find anyone home, state officials said. The agency had no prior history with the family, said Norah West, a spokesperson with the Department of Social and Health Services.

By Saturday, the family's SUV was gone from the driveway, said Bruce DeKalb.