Toxic algae? Carbon monoxide? Family's death at Sierra National Forest still a mystery

Officials continue to investigate but "don't have any answers" as to why a missing family was mysteriously found dead at a remote hiking trail in Sierra National Forest earlier this week.

John Gerrish, Ellen Chung, and their one-year-old daughter, Mija, embarked on a day-long hike at the park on Sunday morning. Their nanny arrived at their Mariposa home on Monday to babysit Mija, but nobody answered the door, prompting concern amongst their friends, according to the Fresno Bee.

Their deceased bodies were found just before 10 a.m. Tuesday on a hiking trail near the Devil’s Gulch area in the Southfork of the Merced River drainage, 15 miles southwest of the entrance to Yosemite.

"This is a very unusual, unique situation," Kristie Mitchell, a spokesperson for the Mariposa County Sheriff’s Office, told the San Francisco Chronicle. "There were no signs of trauma, no obvious cause of death. There was no suicide note. They were out in the middle of a national forest on a day hike."

"We don’t have any answers. This is definitely bizarre," she added.

The case is currently being investigated by the Mariposa County coroner’s office.

The family’s golden retriever was also founded dead with the other three bodies, adding to the mystery of the situation and part of the reason why officials immediately declared the scene a hazmat situation.

Mitchell said another reason it’s a hazmat scene is because carbon monoxide could be at play as there are mines in the area. Investigators also have not ruled out exposure to toxic algae.

The couple originally lived together in San Francisco, however moved to Mariposa to enjoy the outdoor life, Steven Jeffe, a family friend, told the Bee. They enjoyed hiking on the weekends and “loved the great outdoors,” according to the paper.

Gerrish, born in England, was a software engineer at Google, though he worked for SnapChat. Meanwhile, Chung was from Orange, California and was a yoga instructor prior to her pregnancy. She was attending graduate school, hoping to become a marriage and family therapist, the outlet reported.

"They were doting parents," Jeffe said. "For this to happen to them and to their baby girl, it’s exceedingly tragic."

He added the circumstances surrounding his friends’ deaths were "freaky and strange."

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