The Hart family — parents Jennifer and Sarah and their children, who lived in Washington — plummeted from a California cliff 100 feet into the ocean below

When the Hart family — parents Jennifer and Sarah and their children, who lived in Washington — plummeted in their SUV off a California cliff 100 feet into the ocean below, they left behind a possibly unsolvable mystery.

“I can fairly say that several of the questions that have been asked today [will] never be answered,” Mendocino County Sheriff Tom Allman said at a news conference on Wednesday. “It was un-witnessed, we don’t know what happened.”

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Key facts about the crash remain unknown, with the available information complicating instead of clarifying what might have happened.

The incident was first discovered on Monday and California authorities believe it killed everyone involved: the parents and three of the children, whose bodies have been found, and three children who are still missing.

Among other things yet to be determined are how and when the wreck occurred and why the family was traveling.

“We have no evidence and reason to believe that this was an intentional attack,” Allman said. “Certainly people are wondering what caused this.”

According to law enforcement, the family was in a 2003 GMC Yukon XL when they went over a cliff along the Pacific Coast Highway in Northern California, west of Sacramento. Jennifer and Sarah, both 38, were in the front while it is believed their six children, ranging in age from 12 to 19, were in the back.

Sarah and Jennifer were married, according to their family and friends, authorities tell PEOPLE.

None of their kids were wearing seat belts.

Describing a “very confusing scene,” Allman said, “There were no skid marks, there were no brake marks or there was no indication why this vehicle traversed approximately 75 feet over a dirt pull-out and went into the Pacific Ocean.”

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Image zoom The Hart family Facebook

Image zoom The site of the crash in Northern California that killed the Hart family AP/Shutterstock

While only five bodies have been found, Allman said, “We have every indication to believe that all six children were in [the vehicle].”

As the investigation continues, a previous abuse allegation against Sarah and the possibility of recent neglect in the family are drawing scrutiny even as friends describe them as open-hearted.

A California Highway Patrol spokesman tells PEOPLE they cannot discuss the alleged abuse or a possible connection — if any — between it and the recent crash.

“We can’t comment because we don’t really know,” the spokesman says. “As we get info in that, [it] will come to light if there ever was any.”

“You know how sometimes rumors fly, so we don’t want to put anything out there that isn’t true,” he says.

Three days before the crash was reported, Washington State Department of Social and Health Services received a call reporting that the six Hart children appeared to be “potential victims of alleged abuse or neglect,” Norah West, the department’s spokeswoman, tells PEOPLE.

The department sent an employee to the family’s Woodland home but was unable to make contact with them, West says. Social services workers again returned to the Hart’s home on Monday and Tuesday.

The couple had no prior history with the state’s child protective services, West says.

The Dekalbs, a neighbor couple, have come forward to local media to say that they were the ones who reported the suspected abuse on Friday and that when state workers knocked on the Hart’s door, the family was allegedly home but did not answer.

“The next morning when we saw that the vehicle was gone, and then Sunday morning when it still wasn’t there, we figured something was off,” Bruce Dekalb told TV station KGW.

Jennifer and Sarah first began adopting children in 2006, the Oregonian reports. All six of their kids were home-schooled, according to news station KOIN.

Bruce’s wife, Dana Dekalb, said that one of the Hart boys would allegedly come over and ask for food because his mothers did not feed him and his siblings and wouldn’t let them play outside.

“He was asking that we not tell his mom, to hide it [the food] and put it by the fence so he could get to it,” Dana told KOIN, alleging, “They were withholding food from him.”

“I was trying to help them and protect them,” Dana said, adding, “That’s not how I thought it was going to end.”

Image zoom The site of the crash in Northern California that killed the Hart family AP/Shutterstock

Guilty of Domestic Abuse

Records obtained by PEOPLE show that before they lived in Washington, the Harts lived in Alexandria, Minnesota, where Sarah had been charged with hitting one of her daughters after a teacher found bruises on the child’s body.

Court records state that in 2011, 6-year-old Abigail Hart told a teacher that she had “owies” on her “tummy” and back. When the teacher asked Abigail how she got the bruises on her stomach and back, she said, “Mom hit me.”

During police questioning, Sarah admitted to letting her “anger get out of control” and spanking her daughter the day before, according to the criminal complaint against her. But according to the Oregonian, it was Jennifer whom Abigail said had hit her.

“The defendant explained that she and her partner, Jennifer, do not ordinarily use spanking as disciplinary measure in their household. However, they have recently resorted to spanking to deal with Abigail’s behavior,” the complaint states.

Sarah admitted to taking her daughter into the bathroom, bending her over the edge of the bathtub and hitting her on the backside.

Sarah was originally charged with domestic assault and malicious punishment, according to court records. She agreed to plead guilty to the domestic assault charge and the malicious punishment charge was dropped.

In April 2011, she was sentenced to 90 days in jail — which was stayed — and one year of supervised probation, according to court documents.

Still, friends of the Harts reportedly described a radically different situation at odds with the neighbors’ claims and the previous abuse plea.

“They really found the goodness in everybody and I hope they we can all really learn a beautiful lesson from that and carry that legacy on,” friend Max Ribner told KOIN, while another, Zippy Lomax said: “Jen and Sarah really were the kind of parents that I think the world desperately needs.”

KOIN reports that, friends said, they did not see any evidence of abuse. (PEOPLE’s efforts to reach the Harts’ relatives and neighbors for comment were unsuccessful.)

The family purchased property in Woodland in May 2017 and had lived in Oregon, in addition to Minnesota, according to the Oregonian.

Image zoom Devonte Hart (right) in 2014 Johnny Huu Nguyen/AP

Previously in the Spotlight

Among the missing Hart children is 15-year-old Devonte, who was featured in a viral photograph in 2014 showing him hugging a white police officer during a rally in Portland, Oregon, calling for police reform.

“Devonte was in the vehicle but his body has not been recovered,” Sheriff Allman told reporters on Wednesday.

Aside from Devonte, also disappeared are his sisters Hannah Hart, 15, and 12-year-old Sierra Hart, according to Allman.

Bodies of the other Hart children — Markis, 19; Jeremiah, 14; and 14-year-old Abigail — were recovered by authorities and identified by relatives.

California Highway Patrol officials tell PEOPLE that investigators “don’t know” whether Jennifer intentionally drove the SUV over the cliff.

However, authorities believe she pulled into a dirt turnout off of the side of the highway by the ocean before the vehicle continued through the lengthy stretch of land and directly off the cliff into the water.

“I don’t know if they were parked or if they continued to roll,” CHP Sgt. Christopher Dalin said at Wednesday’s news conference. “I don’t know if it rolled over the edge, if it launched over the edge. I won’t have any of that information until we get all of our data back, analyze it and we see what the evidence leads us to.”

Anyone with information regarding the family’s last known whereabouts before the crash is urged to call 707-234-2100.