The speedometer inside a lesbian couple's SUV was 'pinned' at 90 mph after it plunged 100 feet off a California cliff with their six adopted children inside, according to court documents.
Jennifer and Sarah Hart, both 39, were killed when their 2003 GMC Yukon XL crashed off the scenic Pacific Coast Highway in Northern California this week.
Authorities say all eight members of the Hart family, including the six children aged 12 to 19, are presumed dead.
The bodies of three of the children - Markis Hart, 19, Jeremiah Hart, 14, and Abigail Hart, 14 - were located at the bottom of the cliff.
Police believe the couple's three other children - Hannah Hart, 16, Devonte Hart, 15 and Sierra Hart, 12 - were also in the car at the time but their bodies have not yet been found.
Mystery surrounds the horror crash given no one saw their SUV drive off a flat, dirt pullout overlooking the Pacific Ocean.
A search warrant was served at the family's home on Thursday to look for items including a travel itinerary, journals and possible suicide notes.
According to an affidavit for the warrant, cited by Fox 12 Oregon, the speedometer was 'pinned' at 90 mph.
Investigators said there was no evidence the car hit the embankment as it 'traversed towards the tidal zone below', and there were no 'acceleration marks, tire friction marks or braking furrow marks'.
'Based upon the California Highway Patrol investigation, it is their belief "a felony has been committed,"' the court documents stated, according to Fox 12.
Jennifer (back, left) and Sarah Hart (back, right) and their six adopted children were in their SUV when it plunged 100 feet off a California cliff this week
This is an aerial view of the cliff the family plunged over in their car on the Pacific Coast Highway in California. To reach the cliff edge, the women would have had to have driven off the Pacific Highway and traversed 75ft of rugged dirt road before going over the cliff edge
Authorities say all eight members of the Hart family, including the six children aged 12 to 19, are presumed dead after their 2003 GMC Yukon XL was found crashed on rocks
Marcus Mazza, an engineer and reconstruction expert with Pennsylvania-based Robson Forensic, said on Thursday that the SUV was required to have a 'black box' that records accident data.
The recorder would show the car's speed and use of the brakes, according to Mazza.
It could help investigators determine the cause of the crash given there were no skid marks or signs the driver braked in the moments before they went over the cliff.
'There are a lot of unknowns on this,' Mendocino County Sheriff Tom Allman said on Thursday.
'Several of the questions that have been asked today will never be answered.'
To reach the cliff edge at the lookout, the women would have had to have driven off the Pacific Highway and traversed 75ft of rugged dirt road.
'I can tell you it was a very confusing scene because there were no skid marks, there were no brake marks, there was no indication of why this vehicle traversed approximately over 75ft of a dirt pull out and went into the pacific ocean,' Sheriff Allman said.
'We have no reason to believe, we have no evidence, that this was an intentional act. Certainly people are wondering what caused this.
'If this was an intentional act, I truly believe we are going to come to that conclusion.'
Sarah (center) and Jennifer (far right) Hart are pictured with their six adopted children in 2016. Three of their children were found dead alongside them on Monday, while the three others are still missing
Sarah (left) and Jennifer (right), both 39, were killed alongside three of their teenage children when their car crashed off the scenic Pacific Coast Highway in California on Monday
Authorities in Washington state combed through the family's home (above) for information on Thursday. Deputies were looking for bills, receipts or anything else to shed light on why the family left
The two mothers were found dead inside the SUV, while