A Northern California family who were found dead in August died from heat and dehydration during their hike in the Sierra National Forest, officials said.
Mariposa County Sheriff Jeremy Briese made the announcement Thursday at a press conference, saying that investigators considered environmental and other factors before determining that exposure to the elements killed the family of three. Briese said the cause of death was "hyperthermia and probable dehydration."
John Gerrish, Ellen Chung, their 1-year-old daughter, Miju, and their dog were all found dead in August over a mile from their car with "no apparent causes of death," Briese said. Investigators combed the area, searched abandoned mines for signs of entrance by the family, and investigated possible exposure to toxic gases, but found none.
Investigators did not determine the dog's cause of death.
"Heat-related deaths are extremely difficult to investigate," Briese said, adding that investigators spent time combing the rugged mountainside terrain and found the family of three and their dog climbed through treacherous mountain terrain under the exposed sun in triple-digit heat.
Briese also said that the family was found with an empty water bladder. Authorities investigated if they may have ingested river water with anatoxin-A, an element of algae that can be toxic to humans and animals if ingested, but found no evidence they drank any .
The family were found in an area known as Devil’s Gulch in the South Fork of the Merced River in August after being reported missing by a friend. Briese said at the time that there was no obvious cause of death and the area had unreliable cell reception.
The sheriff’s department said they worked to rule out a number of possible causes, including a lightning strike, carbon monoxide, carbon dioxide, cyanide exposure, illegal drugs, alcohol or suicide.
Campgrounds and recreation areas along the river, between the towns of Briceburg and Bagby, were shut down by the Bureau of Land Management following the deaths.