They reveal the cause of death of a family near Yosemite

Mysterious death of a family in Yosemite 0:56

(CNN) -

The mystery behind the deaths of a couple, their young daughter and the family dog, who were found on a hiking trail near Yosemite National Park in August, has come to an end.

The cause of death for Jonathan Gerrish, Ellen Chung and their one-year-old daughter, Miju, was hyperthermia with possible dehydration due to environmental exposure, Mariposa County Sheriff Jeremy Briese said at a news conference Thursday.

"This is a very tragic incident, a tragic situation and it has been very unique from the beginning," Briese said.

• A dead family is found on a hiking trail near Yosemite.

  The authorities do not know what happened

The cause of death for the family dog, Oski, has yet to be determined, according to the sheriff, but they also suspect heat-related problems.

The hyperthermia deaths are the first Briese has seen in her 20s in Mariposa County, she said.

Search and rescue workers found the family on Aug. 17 in a remote area of ​​the Sierra National Forest near the southern fork of the Merced River, according to the sheriff's office.

advertising

The trail has several steep slopes and the couple had hiked approximately 10 kilometers in temperatures ranging from the mid-21s to around 42 degrees Celsius, according to Briese.

The trail had little to no shade, he said.

Briese noted that an empty 2.5-liter water container was found with the couple and that there were no other water containers present.

Investigators were considering a variety of possible causes, from toxic algae reported in the nearby Merced River to noxious gases from abandoned mines near the trail, a spokesperson told CNN at the time of the deaths.

There was no physical evidence on the bodies, so causes such as gunshot wounds or blunt trauma, as well as suicide, were ruled out, considering that there was no note and nothing pointing to that outcome.

• Brian Laundrie: From a trip across the country with Gabby Petito to the confirmation of her death.

  Chronology of the case

In July, the US Forest Service warned that toxic algae had been discovered in the Merced River and urged people not to swim or go through the water or allow their pets to drink it, but this was ruled out as a possible cause. said the sheriff.

"The question of why can never be answered and will remain with us," Chung and Gerrish's relatives said in a prepared statement, describing the pain of losing a loved one multiplied by four as "indescribable."

"Our hearts will never forget the beautiful lives of Jonathan, Ellen, Miju and, of course, Oski. They will remain with us wherever we go and whatever we do," the statement said.

Gerrish worked for Google and had recently started working on Snapchat, according to Steve Jeffe, a friend of the family, who was alerted by friends that the family had not returned home after a day's walk.

"They were amazing people, very generous," Jeffe told CNN.

"They love their daughter very much."

The family's babysitter found no one home when she arrived Monday morning, and after Gerrish failed to show up for work, "the alarms sounded," Jeffe said.

"They were an incredibly loving and caring family," Jeffe said, describing the couple as loving with a very large group of friends.

They confirm that remains found are of Brian Laundrie 1:51

CNN's David Williams contributed to this report.