Officials are investigating whether poisonous algae killed a British software developer, his wife and their one-year-old toddler who were found dead on a remote hiking trail in California.
The bodies of Jonathan Gerrish, 45, his wife Ellen Chung and their daughter Muji – along with their dog Oski – were discovered by search teams on Tuesday in an area of the Sierra National Forest known as Devil’s Gulch.
Maricopa County Sherriff Jeremy Briese said there was no obvious cause of death and he had not dealt with a case like this in his 20 years in the area.
He added toxic algal bloom from the Merced river was being investigated as the cause for what overcame the family, along with potentially gas escaping from abandoned gold mines.
Police are still waiting on the results of post-mortem examinations. Further toxicology reports could take up to six weeks.
California State Water Resources Control Board and Mariposa County are now re-testing the river water for cyanobacterial toxins, which can form in algal blooms.
Searchers began looking for the family after they were overdue on a day hike. They were found on the Savage-Lundy hiking trail near Hites Cove, which was once a thriving mining community after gold was discovered in 1861.
On July 13, Sierra National Forest officials posted a warning about ‘high concentrations’ of algae which can produce ‘extremely dangerous toxins that can sicken or kill people and animals’ in the water in the Merced River at Hites Cove.
A listing on the water board’s online map of harmful algal blooms warned: ‘Water Boards recommends a CAUTION due to illness report. Sample results are pending.’
Briese told The Times: ‘There are those different options that are out there – mineshafts and offgassing potential and we’re learning more with our partners in the Forest Service and public health on the toxicity of the algae blooms that they’re posting about.’
Jonathan Gerrish, his partner Ellen Chung and their one-year-old daughter were found dead near an area called Devil’s Gulch in a remote part of Northern California on Tuesday
Last month, Sierra National Forest officials posted a warning about ‘high concentrations’ of algae which can produce ‘extremely dangerous toxins that can sicken or kill people and animals’ in the water in the Merced River at Hites Cove
This map shows the remote are in Mariposa County, California, where the bodies were discovered on Tuesday
Briese added: ‘I’ve been here for 20 years and I’ve never seen a death, with any case, like this. There’s no obvious indicators of how it occurred… you have two healthy adults, you have a healthy child and what appeared to be a healthy canine all within a general same area, deceased.’
‘It’s frustrating and we’re not going to rest… it’s devastating to everyone,’ he told the Modesto Bee paper.
The state map listing for the location north of Jerseydale, around where the family was found dead this week, warns people to ‘stay away from algae and scum in the water.’
‘Do NOT let pets go in the water, drink the water, or eat scum on the shore,’ the warning continues. ‘Keep children away from algae. Do not eat shellfish from this waterbody.’
State waterboard spokesman Blair Robertson said officials hoped to have the results of the water tests by the weekend.
He added: ‘Our staff is conducting testing of the waterways near where the bodies were located and will make the lab results available to the public as soon as we get them.
‘Autopsies were to be conducted earlier today and we await those findings. Our sincerest condolences to the family and friends of the deceased.’
Mr Gerrish is a software developer for Snapchat, had previously worked for Google and is originally from Lancashire.
Speaking from his home in Bamber Bridge, Lancashire, his father Peter, 70, said: ‘The family are just in shock – heartbroken.’
But asked whether he had received any further updates or was in contact with US authorities, the grandfather added: ‘We haven’t heard anything more.’
The state map listing for the location north of Jerseydale where the young family were found dead, warns people to ‘stay away from algae and scum in the water.’
‘Do NOT let pets go in the water, drink the water, or eat scum on the shore,’ the warning says. ‘Keep children away from algae. Do not eat shellfish from this waterbody.’
The family’s dog was found dead along with its owners by search teams
Kristie Mitchell, a spokeswoman for the sheriff’s office has said investigators are still working to determine the cause of their deaths and ‘looking at all possibilities.’
‘It could be a carbon monoxide situation. That’s one of the reasons why we’re treating it as a hazmat situation,’ she said.
‘There are several abandoned mines up in the area and in an abundance of caution or recovery team is taking precautions for any poisonous gases, particles in the area,’ Mitchell added. ‘So far, there has been no measurable poisons registered.’
Mitchell also did not rule out possible exposure to toxic algae. She noted that the bodies of the deceased showed no signs of trauma, and no suicide note was found.
‘It is a very bizarre situation,’ she said.
According to a Reuters article published in 2013, two gold and silver miners died in Colorado after being exposed to fatal levels of carbon monoxide, and 19 others fell ill.
Dr Mike Nelson, professor of mining engineering at University of Utah, cast doubt on the theory that carbon monoxide emissions from an old gold mine were possibly to blame for the deaths.
During a phone interview with the DailyMail.com on Wednesday, Nelson explained that gold mines are not known to produce carbon monoxide, and even if the gas were present, it would have gone up into the air.
He also noted that the family were found outdoors and not in an enclosed space where exposure to carbon monoxide could be lethal.
The bodies were located near the Hite Cove trail, known particularly in springtime to have spectacular wildflower displays
Gerrish, a native of England, had worked as a software engineer at Google. Chung was from Orange, California, but was of Korean descent
If the medical examiner decides to conduct toxicology tests, results could take up to six weeks.
A friend had reported the family missing at 11pm on Monday evening after Gerrish and Chung failed to show up for work that day, reported Fox 26 News.
Gerrish and Chung, from Orange, California, were last heard from early Sunday, when they uploaded a photo of a backpack. Rosanna Heaslett, the family friend, said they hiked on weekends.
The family’s gray Ford Raptor was located near the Sierra National Forest gate early Tuesday. The bodies of the couple, their daughter and pet dog were found between 9.30am and 10am.
‘This is never the outcome we want or the news we want to deliver, my heart breaks for their family. Our Sheriff’s Chaplains and staff are working with their family and will continue to support them during this heartbreaking time,’ said Sheriff Jeremy Briese.
The sheriff’s office is investigating the deaths along with the California Department of Justice.
The remote area where the bodies were found had no cellphone service, Mitchell said. It was close to the Hite Cove trail, known particularly in springtime to have spectacular wildflower displays.