"We do have reason to believe, however, that the crash was intentional", he added.
During a telephone press conference that evening, a California Highway Patrol spokesperson revealed that Hart's vehicle stopped a pullout and then accelerated over the cliff, a distance of about 70 feet.
Baarts explained the electronic information in combination with the lack of skid marks led authorities to believe the crash was no accident.
On Sunday, authorities announced that data from the vehicle's software suggested the crash was deliberate.
Authorities are still searching for the 3 missing children.
Authorities are still searching for the remaining three siblings - 16-year-old Hannah, 15-year-old Devonte and 12-year-old Sierra - but have said they believe they may have also been in the auto at the time of the crash. The missing children may have been washed out to sea, authorities say.
"This specific location is very hard to search because the ocean currents and tides are strong, it's unpredictable, and the murkiness of the water makes it hard to see", Captain Greg Van Patten of the Medocino County Sheriff's office told the Associated Press (AP) news agency.
"We can't get divers into that area".
However, AP reports that Max Ribner, a family friend, bristled at the implication that the couple would've intentionally harmed their six adopted children.
Before the Harts moved to Washington, they had lived in Minnesota, where Sarah Hart pleaded guilty to misdemeanor domestic assault involving one of the children in 2010, according to court records from Douglas County.
Hart family crash: No skid marks, signs of braking in fatal California SUV plunge
The bodies of Jennifer and Sarah Hart and their children Markis, 19, Jeremiah, 14, and Abigail, 14, were discovered on March 26. Searchers were looking for Hannah Hart, 16; Sierra Hart, 12; and Devonte Hart, 15.
Devonte Hart hugs Portland police Sergeant Bret Barnum at a rally in Portland in 2014.
After the Friday visit, Child Protective Services tried to visit the family twice more, on Monday and Tuesday, to no avail, according to the Washington State Department of Social and Health Services.
One person in their neighborhood told KWG8 that Devonte said his mothers didn't feed them and withheld food as punishment. The boy asked her to leave food in a box by the fence for him, she said.
DeKalb said that he had called Child Protective Services March 23 and they had arrived at the house just after Jennifer Hart came home from work but that she didn't answer the door.
A search warrant affidavit was granted in Clark County in connection with this investigation for items including travel itinerary, bank records, cell phone records, credit card billing statements, bank receipts, notes, journals and possible suicide notes. The agency says their SUV was driving Monday on the Pacific Coast Highway when it pulled into a dirt turnout and continued driving off the cliff.
Family friends disputed that the parents were abusive.
The Department of Social and Health Services say they will classify the children who were killed "as potential victims of alleged abuse or neglect".
Zippy Lomax, a photographer who knew the Harts, called it "a tragic accident of a magnitude that can not be measured".