Jennifer and Sarah Hart drugged themselves and their six children, then drove an SUV carrying the whole family off a cliff, killing them, a Mendocino County, California, jury ruled Thursday.

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The jurors returned their decision after a 57-minute deliberation, which came after a two-day coroners inquest into the family's death, Oregon Live reported. During the inquest, police made public evidence that they said supported the women deliberately planning the crash.

Jennifer and Sarah Hart, both 38, had six adopted children: 12-year-old Sienna Hart, 14-year-old Abigail Hart, 14-year-old Jeremiah Hart, 15-year-old Devonte Hart, 16-year-old Hannah Hart and 16-year-old Markis Hart, according to previous Cox Media National Content Desk reports.

In March of 2018, the Woodland, Washington, family drove south to Mendocino County, California. The women administered some kind of Benadryl to the children. Then, Jennifer Hart, drunk, drove the GMC Yukon carrying the whole family off a cliff, evidence presented in the inquest showed, according to Oregon Live.

The bodies of Jennifer Hart, Sarah Hart, Abigail Hart, Jeremiah Hart and Markis Hart were found at the scene. The bodies of Sienna Hart, Hannah Hart and Devonte Hart were never found, but police said they believe they also died in the crash.

Markis Hart had the equivalent of 19 doses of Benadryl in his system, and the other children had similar levels, according to evidence presented at the inquest. Sarah Hart had the equivalent of 42 Benadryl doses. Jennifer Hart was found with five shots’ worth of alcohol in her system.

Other evidence presented at the inquest focused on information found on three devices: the family’s GPS system, the SUV’s “black box”-style computer and Sarah Hart’s cellphone.

After leaving the family home the day of the deaths, the following internet searches were made on Sarah Hart’s cellphone, presumably by her: “Can 500mg of Benadryl kill a 120-pound woman?” “Is death by drowning relatively painless?” “How long does it take to die from hypothermia in water while drowning in a car?”

A Garmin GPS recovered after the crash showed the route the Harts took, California Highway Patrol investigator Jake Slates testified. It included an 18-minute stop at a Walmart to buy generic-brand Benadryl. Investigators learned that Jennifer and Sarah Hart often gave the children Benadryl to make them sleep during long car rides, Slates said. He testified investigators believe the children were asleep when the SUV drove off the cliff.

The vehicle's "black box" showed that Sarah Hart drove off the cliff at full speed, never applying the breaks, testified Officer Timothy Roloff, of the California Highway Patrol's Multidisciplinary Accident Investigation Team.

“There are times, maybe if you’re merging on the freeway, that you hit 100% throttle, but if you’re at a cliff edge and you’re with your family, how often do you apply 100% throttle?” Roloff asked. “Ultimately, it seemed like a very unfortunate, intentional event.”

Investigators believe a March 23 visit from a social service worker prompted the mothers to drive off the cliff, Slates said. The family had moved multiple times, and Jennifer and Sarah Hart were reported for possible abuse in each location, he said.

“Based on the Harts’ past history, patterns we see of child abuse, this was another case where they ran,” Slates said.

The jurors ruled that Jennifer and Sarah Hart died by suicide, and that the six kids died from their mothers’ intentional act. Juror Tony Howard told Oregon Public Broadcasting that hearing the evidence during the inquest was difficult for the jury.

“I’m going to be really honest with you guys. Coming up with the decision wasn’t the hard part,” Howard said. “Dealing with the whole tragedy was the hard part.”

Authorities said in a Friday press conference that they hope the inquest can bring closure to the families and people who knew the Harts.