WOODLAND, Wash. >> They were known as the Hart Tribe, a free-spirited family of two women and their six adopted children who raised their own food, took spontaneous road trips and traveled to festivals and other events, offering free hugs and promoting unity.

Their final journey ended not in hugs all around but in tragedy.

All eight were presumed dead after their SUV plunged off a 100-foot cliff along a seaside California highway in a mysterious wreck discovered Monday — three days after child-welfare authorities were called to the Harts’ rural Washington state home to investigate possible abuse or neglect.

“We know that an entire family vanished and perished during this tragedy,” Mendocino County Sheriff Tom Allman said Wednesday as he appealed for help retracing where the family had been.

Investigators have yet to determine the cause of the crash, and the sheriff said there is “no evidence and no reason to believe that this was an intentional act.”

At the same time, he said there were no skid marks and no sign the brakes were applied at the highway pull-off area where the vehicle went over.

The case has thrown a spotlight on the Hart family’s previous run-ins with the law and neighbors’ concerns about the youngsters.

Friends described married couple Jennifer and Sarah Hart as loving, inspiring parents who promoted social justice and exposed their “remarkable children” to art, music and nature.

One of the children, 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. The boy was holding a “Free Hugs” sign.

The Hart Tribe also went to events such as rallies for presidential candidate Bernie Sanders, often showing up in matching T-shirts.

They moved to Woodland, Washington, outside Portland, in the spring of last year, partly overwhelmed by the media coverage. The multi-racial family had received death threats, a family friend said.

“This is a tragic accident of a magnitude that cannot be measured,” said Zippy Lomax, a photographer who knew the Harts. “They were really radiant, warm, adventurous, inspiring people. They were always on some grand adventure, and the kids were living this life that was kind of like this dream.”

She added: “When they showed up to an event, they made an impression. They shattered a lot of norms, and they did not shy away from controversy or adversity.”

But neighbors said they saw signs that caused them to worry about how the homeschooled children were being cared for.

Next-door neighbors Bruce and Dana DeKalb said they called child services last Friday because Devonte, now 15, had been coming over to their house asking for food.

Dana DeKalb said Devonte told her that his parents were “punishing them by withholding food.” He came over almost every day for a week and asked her to leave food in a box by the fence for him, she said.

Washington state child-protective services opened an investigation Friday and tried to make contact with the family three times but weren’t able to reach them, said Norah West, a spokeswoman with the state Department of Social and Health Services. The agency had no prior history with the family, she said.

The DeKalbs also recounted that three months after the family moved into the home on 2 acres with a fenced pasture last May, one of the girls rang their doorbell at 1:30 a.m.

She “was at our door in a blanket saying we needed to protect her,” Bruce DeKalb said. “She said that they were abusing her.”

In 2011, Sarah Hart pleaded guilty to a domestic assault charge in Minnesota. Her plea led to the dismissal of a charge of malicious punishment of a child, according to court records.

According to a criminal complaint, a 6-year-old girl told a teacher at her elementary school that she had “owies” on her tummy and back and said, “Mom hit me.” Sarah Hart told authorities “she let her anger get out of control” while spanking her daughter.

Max Ribner, who has known the family since 2012, said allegations from neighbors don’t square with what he knows about the Harts.

“They are beautiful examples of opening arms to strangers, helping youth, supporting racial equality,” Ribner, who lives in Portland, said. “They brought so much joy to the world. They represented a legacy of love.”

The bodies of the two women, both 39, were recovered along with those of Markis Hart, 19; Jeremiah Hart, 14; and Abigail Hart, 14. Hannah Hart, 16; Sierra Hart, 12; and Devonte were also believed to have been in the SUV, and authorities continued to search for their remains.

Bill Groener, 67, was a next-door neighbor of the Harts when they lived in West Linn, Oregon, and said the kids stayed indoors most of the time. He said the family didn’t eat sugar, raised their own vegetables, had animals and went on camping trips.

“There was enough positive there to kind of counteract the feeling that something maybe wasn’t quite right,” Groener said.