Parents Sarah and Jennifer Hart and three of their adopted children - 19-year-old Markis, 14-year-old Jeremiah and 14-year-old Abigail - were confirmed dead on Wednesday by authorities in Mendocino County after a passerby spotted their auto at the bottom of the cliff overlooking the Pacific Ocean.
They found that the vehicle had stopped then suddenly accelerated off Highway 101 sending the auto into the ocean 70-feet below reports NBC.
The family's SUV appears to have been stopped by the side of the road in Mendocino County, about 180 miles (290 kms) north of San Francisco, before accelerating to as fast as 90 mph (145 kph) and hurtling off a cliff, acting Assistant CHP Chief Greg Baarts told reporters on Sunday. "We do have reason to believe, however, that the crash was intentional".
"Based upon the California Highway Patrol investigation, it is their belief 'a felony has been committed, '" according to court documents.
His adoptive sisters - 16-year-old Hannah Hart and 12-year-old Sierra Hart - were also missing after the family's vehicle plummeted off a cliff near Mendocino on March 26. Baarts said that as far as he knew, investigators had not found a suicide note. In the image, tears stream down his face as he embraces a white officer in the middle of a demonstration in Portland, Oregon, related to the fatal police shooting of Michael Brown in Ferguson, Missouri.
But days before the wreck was discovered, neighbours called Washington state child-welfare authorities to say one of the youngsters had been coming to their house nearly daily asking for something to eat and complaining that his parents were withholding food as punishment. Devonte had been holding a sign offering "Free Hugs".
"The most likely cause of that reading is the shock from the impact", he said, adding that when a vehicle collides with something, the speedometer will lock at a certain speed.
Two weeks ago, Bruce and Dana DeKalb, next-door neighbors of the Harts in Woodland, Wash., called state Child Protective Services because Devonte had been coming over to their house nearly every day for a week, asking for food.
Investigators last week obtained a search warrant for the family's home in Woodland and looked for itineraries, bank and phone records, credit card receipts, journals or other documents that might shed light on the case.
The vehicle was discovered on 26 March, three days after child protective services in Washington state - where the family lived - opened an investigation.
One person in their neighborhood told KWG8 that Devonte said his mothers didn't feed them and withheld food as punishment.
The department said it had no history with the family. Sarah Hart came home not long afterward, DeKalb said, and by Saturday morning the family and their vehicle were gone.
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 adoptive daughter, court records show. Family friend Max Ribner last week took issue with the notion it was something other than a tragic accident.