SAN FRANCISCO (AP) — Investigators are considering whether toxic algae blooms or other hazards may have contributed to the deaths of a Northern California couple, their baby and the family dog on a remote hiking trail, authorities said.

The area in the Sierra National Forest where the bodies were found on Tuesday had been treated as a hazmat site after concerns were raised about the deaths being linked to potentially toxic gases from old mines nearby.

UPDATE: San Francisco Family Found Dead in Sierra Foothills Not Exposed to Chemicals from Mine

But the hazmat declaration was lifted Wednesday, and Mariposa County Sheriff Jeremy Briese said he didn’t believe the mines were a factor, the Fresno Bee reported Thursday.

“This is a very unusual, unique situation,” said Kristie Mitchell, a spokesperson for the sheriff’s office. “There were no signs of trauma, no obvious cause of death. There was no suicide note.”

Family Found Dead in Sierra Nat'l Forest

John Gerrish, his wife, Ellen Chung, their 1-year-old daughter, Miju, and their dog were all found dead on a hiking trail near Hite’s Cove in the Sierra National Forest. (CBS Fresno via YouTube)

John Gerrish, his wife, Ellen Chung, their 1-year-old daughter, Miju, and their dog were all found dead on a hiking trail near Hite’s Cove in the Sierra National Forest. A family friend had reported them missing Monday evening.

The area around Hite’s Cove was the site of a hard rock gold mining operation in the mid-19th century.

The bodies were transported to the coroner’s office in Mariposa for autopsies and toxicology exams, Mitchell said.

The State Water Resources Control Board said Thursday it was testing waterways in the area for any toxic algae blooms.

A helicopter hovers over a remote area northeast of the town of Mariposa Aug. 18, 2021. According to the Mariposa County Sheriff’s Office, the area is reported to be where a family and their dog were found dead on Tuesday. (Craig Kohlruss via AP)

The couple were known to be avid hikers. Their friend, Mariposa real estate agent Sidney Radanovich, said Gerrish was a San Francisco-based software designer who, with his wife, “fell in love with the Mariposa area” and bought several homes there, a residence for themselves and rental investments.

According to the Fresno CBS affiliate, Gerrish was from the United Kingdom and met Ellen Chung in San Francisco before they relocated to Mariposa during the pandemic in 2020. SFGate.com reported that Gerrish had been working for Snapchat.

“They were such a loving couple. They loved each other quite a bit,” Radanovich told the Chronicle. “He loved showing the baby all sorts of things and explaining them to her.”

A Mariposa County deputy sheriff stands watch over a remote area near where a family and their dog were reportedly found dead the day before. (Craig Kohlruss via AP)

The sheriff’s office was investigating the deaths along with the California Department of Justice.

Sheriff Jeremy Briese said chaplains and staff were counseling family members.

“My heart breaks for their family,” he said.

The remote area where the bodies were found had no cellphone service, Mitchell said. The hiking trail ran through an area of forest known particularly in springtime to have spectacular wildflower displays.

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