Updated 6:30 p.m.

Devonte Hart, a boy who in 2014 was at the center of a viral photo showing his tender embrace with a Portland policeman, is missing and at least five family members are dead after their SUV plunged off a cliff along the Northern California coast.

Devonte, now 15, is believed to have been in his family's vehicle as it went off a Pacific Coast Highway cliff Monday, killing his parents and at least three siblings.

Authorities continued late Wednesday to scour the crash scene, including the ocean, in search of the children believed to have been in the car, the Mendocino County Sheriff's Office said.

The victims, former West Linn residents who had moved to Woodland, Washington, plunged to their deaths when their 2003 GMC veered off Route 1 near the town of Westport and fell 100 feet, eventually landing on its roof on a large rock at the shoreline.

The three children killed weren't using seat belts and "came out" of the vehicle at some point, the California Highway Patrol said. The women were found inside wearing safety restraints.

Authorities on Wednesday identified the adults as Jennifer Jean Hart, the driver, and Sarah Margaret Hart, both 38. The Hart children killed were Markis, 19, Abigail, 14, and Jeremiah, 14.

The sheriff's office said they can't find siblings Devonte, Hannah, 16, and Sierra, 12. All six kids were adopted by the married couple, the sheriff's office said.

The crash occurred days after authorities in Washington tried to visit the family home multiple times after receiving reports of abuse and neglect concerning the children.

At a news conference Wednesday, Mendocino County Sheriff Tom Allman said officials have "every indication to believe" all six children were in the vehicle when it went off the cliff.

"We have no evidence and no reason to believe this was an intentional act," Allman said. He also said there are no skid marks or brake marks indicating why the vehicle went off the cliff. He said an investigation is ongoing.

The sheriff appealed for the public's help in retracing where the family had been in recent days.

In 2014, a photograph of a tear-streaked Devonte hugging Sgt. Bret Barnum during a tense "Black Lives Matter" demonstration in downtown Portland garnered global attention.

The photo, originally published by The Oregonian/OregonLive, was featured in national media, reached No. 1 on the social-sharing website Reddit and drew widespread Facebook attention.

"Jen and Sarah were the kinds of parents this world desperately needs," said Portland photographer Zippy Lomax, who had known the family since 2012. "They loved their kids more than anything else."

The Hart family was a regular at Oregon festivals and shows, Lomax said, including the Beloved festival in Tidewater. They also joined presidential candidate Bernie Sanders onstage during a 2016 rally in Vancouver.

"They weren't plugged in to the technology," she said. "They preferred to lay [around] and read books and hang out with their chickens."

Devonte frequently wore the "Free hugs" sign that produced the famous photograph. Lomax said the sign prompted other memorable interactions as Devonte and strangers embraced.

But the reaction to that 2014 moment overwhelmed the family, Lomax said, with much negative attention focused on the multiracial family with lesbian parents.

"They got a lot of negativity from that, and they kind of closed off for a while, honestly," Lomax said.

The family frequently traveled together, Lomax said, taking scenic routes to explore new places and new vistas. She imagines that's what they were doing when the fatal crash occurred.

Court records and recent neighbors, however, portray a family that was at times strained.

The Harts and their children left their home Friday shortly after no one answered the door for a visit by the authorities, according to neighbors and the Clark County Sheriff's Office.

Bruce and Dana DeKalb, who lived next door, said they rarely spoke with the family, which about 10 months ago moved to the remote wooded area in northern Clark County.

Dana DeKalb said Devonte had come to their home a dozen times to ask for food, saying his parents had withheld it as a form of punishment. The teen would ask the couple to leave the food by the fence they shared so his parents wouldn't know, she said.

Such interactions prompted the DeKalbs to contact authorities, they said Wednesday outside their home.

A Clark County deputy accompanied Cowlitz County Child Protective Services to the Hart family's home Friday but nobody answered the door, Sgt. Brent Waddell, a Clark County Sheriff's Office spokesman, told The Oregonian/OregonLive on Wednesday.

The family and its SUV were gone the next day, Bruce DeKalb said.

Norah West, a spokeswoman for the Washington State Department of Social and Health Services, on Wednesday said the agency attempted to contact the family three times after receiving reports of abuse or neglect but was unsuccessful.

Court records in Minnesota show Sarah Hart received a 90-day suspended jail sentence and a year of probation in 2011 after her six-year-old daughter arrived at school with bruises on her stomach and back. The girl told a teacher, "Mom hit me," according to records.

Shortly after, the family moved to West Linn, where they lived until relocating to Woodland.

Bill Groener, who lived next door to the family in West Linn, said they kept to themselves and the kids mostly stayed indoors – even in good weather. Groener said the only contact he had with the family is when they went out to get the mail.

"Something," Groener said, "just didn't seem right."

Oregonian/OregonLive staff writers Eder Campuzano, Tom Hallman, Jr., Mike Rogaway and Molly Young, along with The Associated Press, contributed to this report.

-- Shane Dixon Kavanaugh

skavanaugh@oregonian.com

503-294-7632 || @shanedkavanaugh