The 31-metre drop killed the women, both 39, and their children Markis Hart, 19; Jeremiah Hart, 14; and Abigail Hart, 14. Hannah Hart, 16; Devonte Hart, 15; and Sierra Hart, 12, have not been found.

The Harts lived in Woodland, Washington, a small city outside Portland, Oregon, and had a recent visit from Child Protective Services, Clark County sheriff's Sergeant Brent Waddell told The Associated Press.

He said the sheriff's office later entered the house and found no obvious signs of trouble or violence. It appeared the family planned a short trip because they left behind a pet, chickens and most of their belongings.

Next-door neighbours Bruce and Dana DeKalb said they called child services on Friday because they were concerned that Devonte Hart, who hugged the officer at the protest, was going hungry. They said he had been coming over to their house too often in the past week asking for food.

The DeKalbs also recounted that three months after the family moved into the home on 2 acres with a fenced pasture in May 2017, one of the girls rang their doorbell at 1.30 am.

She "was at our door in a blanket saying we needed to protect her," Bruce DeKalb said. "She said that they were abusing her. It haunted my wife since that day."

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, online court records say.

Bill Groener, 67, was a next-door neighbour of the family when they lived in West Linn, Oregon, and said the kids were home-schooled.

"They stayed indoors most of the time, even in really nice weather," Groener said.

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.

He said they were neighbours for about two years and that "privacy was a big thing for them."

The family got attention after Devonte Hart was photographed during a 2014 protest in Portland, Oregon, over a grand jury's decision not to indict a police officer in the shooting of a black man in Ferguson, Missouri.

The boy, holding a "Free Hugs" sign, stood crying. A Portland officer saw his sign and asked if he could have a hug, and an emotional Hart embraced him in a picture that was widely shared.

At the time, Jennifer Hart wrote on social media: "My son has a heart of gold, compassion beyond anything I've ever experienced, yet struggles with living fearlessly when it comes to the police. ... He wonders if someday when he no longer wears a 'Free Hugs' sign around his neck, when he's a full-grown black male, if his life will be in danger for simply being."

The family travelled to many festivals throughout the area - including events for presidential candidate Bernie Sanders - and were known for wearing matching T-shirts.

Zippy Lomax, a Portland photographer who knew the Harts, told the Oregonian/Oregonlive.com that the reaction to the 2014 photo overwhelmed them, with negative attention focused on the multiracial family with lesbian parents.

"They kind of closed off for a while, honestly," Lomax told the newspaper. But she added that "Jen and Sarah were the kind of parents this world desperately needs."