LOS ANGELES -- On the northern California coast, police are searching for answers after an SUV went off a cliff. Three children are still missing, including a boy you may recognize from a famous photo. His adoptive parents and at least three other siblings are dead.

A special accident investigation team is using drones to figure out how the Hart family vehicle plunged off a 100-foot ocean overlook. Sheriff Thomas Allman believes the parents, Sarah and Jennifer Hart, were in the front, and their six adopted children in the back. None of them were wearing seat belts.

"I could tell you it was a very confusing scene, because there are no skid marks," said Allman.

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The Hart family lived just outside Portland and loved to hike and camp. A picture of one of the kids, Devonte, hugging a Portland police officer in 2014 during a protest against the Ferguson police shooting, went viral. His parents championed social justice issues. But neighbors Bruce and Dana Dekalb saw something different.

Sarah and Jennifer Hart with their 6 children in an undated photo KOIN-TV

"Their daughter is telling us, 'Please, please, please,' begging us not to go back. They're abusing her," said Dana Dekalb. "And then Devonte coming over here and telling us he's being starved to death."

The Dekalbs say recent cries for help from the Hart children prompted them to call Child Protective Services last Friday.

"I was trying to help them and protect them and this is the result," said Dana.

Sarah Hart pleaded guilty to domestic assault in Minnesota back in 2011 after bruises were found on one of the children's back and stomach. Just the last week, CPS case workers had gone by the family's home three times to check on the children.