Investigators were perplexed when the deaths of Ellen Chung, John Gerrish, their 1-year-old daughter Miju, and their family dog Oski were discovered on a central California hiking route on August 17.
Their bodies, discovered in a tiny valley known as the Devil’s Gulch, exhibited no evident wounds or evidence of trauma – no hint that an animal or another human was to blame.
Was it a lightning strike? Carbon monoxide or other gas emissions from adjacent abandoned mines? Cyanide poisoning? Suicide?
All of these possibilities were ruled out one by one.
The deaths remained unsolved for two months.
But on Thursday, sheriff’s deputies in Mariposa, a small mountain town east of San Jose that serves as a gateway to the Sierra National Forest and Yosemite National Park, announced they had finally identified the cause: heat.
Sheriff Jeremy Briese told reporters they had determined the family died of hyperthermia and possible dehydration due to excessive heat.
Hyperthermia is an abnormally high body temperature brought on by the failure of heat-regulating mechanisms in the body due to environmental conditions, according to the National Institutes of Health.
The cause of death for the dog was still being determined but was believed to be the same, according to Briese.
“This is an unfortunate and tragic event due to the weather,” Briese said.