John Gerrish and his family were found dead in Sierra National Forest Tuesday. Authorities believe toxic algae is to blame. As of Friday morning, the cause of death wasn’t yet confirmed. The family of three was still undergoing autopsies and toxicology exams, but officials suspect dangerous blooms in the area may have been the cause. The Mariposa coroner’s office has not yet released its official report.

According to reports, investigators are considering whether toxic algae blooms could have caused the deaths of John Gerrish, his wife, Ellen Chung, and their 1-year-old daughter, Miju. There are still no definitive answers, though officials are scanning the remote area of Sierra National Forest for clues. The State Water Resources Control Board confirmed it was testing nearby waterways for toxic algae blooms.

Does Sierra National Forest have toxic algae? Investigators believe toxins to blame in death of California family.
Does Sierra National Forest have toxic algae? Investigators believe toxins to blame in the death of the California family. Photo Credit: Twitter

Harmful “algae blooms” are the product of a rapidly growing algae population in freshwater or marine water systems, according to the National Oceanic and Atmospheric Administration. They can often “grow out of control and produce toxic or harmful effects on people,” the organization wrote on its website. The toxic algae blooms can cause severe illnesses that can be “debilitating or even fatal.”

It’s still not clear whether John Gerrish and his family were affected by these harmful blooms, however, authorities haven’t reported any other leads. On Tuesday, when the California family was found, authorities declared it a hazmat situation, believing carbon monoxide poisoning could have been a factor in their deaths. It was believed that carbon monoxide had escaped from the abandoned mines present in the area.

The old gold mines were active in the mid-1800s and have been abandoned for quite some time. The California family was found near the mining area, known as Devil’s Gulch, and authorities thought toxins trapped underground had been released into the air. Dave Given, a resident of Mariposa County, said on Wednesday that there were over 300 mines in Mariposa County as of 1950. He admitted that there could be more because the figure only considered “the registered mines.”

Givens speculated that one of many toxic gases from the old mines could have been a factor in the family’s death. He told hikers to “stay out of abandoned mines” because “there’s no maintenance.” He explained that “timbers rot, gasses collect. Not a good place.”

But as of Wednesday night, the mine theory has since been shot down and the hazmat declaration was lifted. Mariposa County Sheriff Jeremy Briese said that he no longer believed the mines were a factor.

John Gerrish, Ellen Chung Found Dead In Sierra National Forest With 1-Year-Old Daughter Miju: What Happened To The California Family?
John Gerrish, Ellen Chung Found Dead In Sierra National Forest With 1-Year-Old Daughter Miju: What Happened To The California Family? Photo Credit: PingPong916 / Shutterstock.com

Briese said in a statement that “I don’t believe it’s connected to a mine,” and while “we don’t know the cause… we won’t rest until we figure it out.” It’s possible that the ongoing autopsies and toxicology tests will uncover the answers. The bodies of John Gerrish, his wife, and his 1-year-old daughter are being held in Stanislaus County. The family’s dog, a golden retriever names Oski, who was also found dead, will receive an autopsy from Tulare County and UC Davis.  

Kristie Mitchell, a spokesperson for the sheriff’s office admitted that “this is a very unusual, unique situation. There were no signs of trauma, no obvious cause of death. There was no suicide note.” The family, who was found dead Tuesday on Savage-Lundy Trail in Devil’s Gulch near Hites Cover, was reported missing on Monday by one of their neighbors. The family had left for the hike over the weekend and never returned. John Gerrish failed to report to his software engineering job and it raised red flags.

It was reported that the couple was avid hikers. Sidney Radanovich, a friend of the family, explained that their couple “fell in love with the Mariposa area,” and even bought several properties as rental investments – leaving one for their own residence. She said that “they were such a loving couple” and that “they loved each other quite a bit. He loved showing the baby all sorts of things and explaining them to her.”