The California family that died in August while hiking in Sierra national forest was killed by extreme heat and probable dehydration, law enforcement officials announced on Thursday, providing some answers to a mystery that had baffled investigators for months.
The Mariposa county sheriff’s department believes 45-year-old Jonathan Gerrish, originally from the UK, his wife, 30-year-old Ellen Chung, their one-year-old daughter, Miju, and their dog, Oski, died while on a hike on the Hites Cove trail on 15 August. Temperatures were as high as 109F (42.8C) that day, and the majority of the eight-mile trail has little shade or trees.
“Heat-related deaths are extremely difficult to investigate,” said Jeremy Briese, the Mariposa county sheriff.
The unusual case had stumped law enforcement since 17 August when officials found the bodies of the family and their dog on the remote hiking trail near the Devil’s Gulch area in Sierra national forest. They were all found in the same area, and it appeared they had completed most of the hike, Briese said.
Their vehicle was located a little more than a mile away, near a gate to the forest. A friend had reported the family, described as avid hikers, as missing. An 85-ounce water container the family had with them was empty, and they had no other water. There is no cellphone reception on the trail.
When officials found the bodies, no signs of the cause of death were immediately clear, and the area was briefly treated as a hazmat site. The sheriff’s department described the case as an “unusual, unique situation”.
The case transfixed the state and prompted national news coverage as law enforcement and online sleuths sought to determine what happened to the family.
In the months since, officials had considered but ultimately ruled out a number of other causes of death, including carbon monoxide, exposure to gas from mines in the area, a lightning strike, suicide and drugs.
Officials also considered the possibility the family had been killed by toxic algae after water sources in the area tested positive for it, but said at the news briefing they had found no evidence to support this as the cause of death. In September, Sierra national forest closed trails near where the family died, citing “unknown hazards found in and near the Savage Lundy trail”.
Temperatures were in the 70s when the family started their hike, but climbed as high as 108F as they made their way through the trail. Officials were unable to determine the dog’s cause of death, but believed it was also related to the heat.
The circumstances of their deaths, with the entire family and dog found together, were unusual, Griese acknowledged, but his office was confident in their findings. More than 30 local, state and federal agencies were involved in the investigation. The FBI is analyzing a cellphone found with the family, which investigators hope will provide more information about what unfolded on the trail that day.
The deaths, Griese said, were weather-related and there are no other known hazards to the public on the trail.
A friend of the family previously told the San Francisco Chronicle that Gerrish was a San Francisco-based software designer who “fell in love with the Mariposa area” and bought several homes there. The Fresno Bee reported that Gerrish worked remotely for Snapchat while Chung, who was from southern California and had previously worked as a yoga instructor, was in graduate school to become a marriage and family therapist.
“From everyone we talk to they were extremely happy, outgoing and loved finding Mariposa, and they were able to work from home and enjoy nature, and in the short time they were here they made a lot of friends,” Briese told the Chronicle.
In a statement read by a spokesperson for the sheriff’s office, the Gerrish-Chung family said their loved ones’ deaths had been a “pain almost beyond words”, worsened by its mysterious nature. They thanked officials for their work on the case and efforts to provide answers.
“Our hearts will never forget the beautiful lives of Jonathan, Ellen, Miju and of course, Oski,” the statement said. “They will remain with us wherever we go and in whatever we do. In the future, when we sit beneath the trees listening to the wind soaring through the branches, we will hear them and we will remember.”