Investigators say no gas or weapons were used to kill family found dead on a California hiking trail

Investigators have ruled out exposure to mine shaft gases and the use of weapons in the mysterious death of a British software developer and his family on a remote California hiking trail.

Jonathan Gerrish, 45, his wife Ellen Chung, their one-year-old daughter Muji and their dog Oski, were found by search teams on Aug. 17 in an area of ​​the Sierra National Forest known as Devil’s Gulch.

Police said the bodies showed no signs of trauma and no suicide note was found.

Toxic algae has not yet been ruled out, and samples were taken for testing from the Merced River and Snyder Creek, as well as containers the family carried.

Authorities are still waiting for toxicology reports and cell phone data before making a decision on how the family died.

In its first nearly week-long update, the Mariposa County Sheriff’s Office provided new details on the timeline, indicating that their family was spotted by a witness heading to the track on the morning of August 15.

Detectives believe they managed most of a challenging 8.5-mile loop, including five miles down a steep slope with little shade as temperatures soared above 100 degrees, before collapsing on their return to their truck.

Jonathan Gerrish, 45, his wife Ellen Chung, their one-year-old daughter Muji (pictured) and their dog Oski, were found by search teams on Aug. 17 in an area of ​​the Sierra National Forest known as Devil's Gulch.

Jonathan Gerrish, 45, his wife Ellen Chung, their one-year-old daughter Muji (pictured) and their dog Oski, were found by search teams on Aug. 17 in an area of ​​the Sierra National Forest known as Devil’s Gulch.

The couple was last heard from early Sunday when they uploaded a photo of a backpack.  Pictured: Jonathan with baby Muji

The couple was last heard from early Sunday when they uploaded a photo of a backpack.  Pictured: Jonathan with baby Muji

The couple was last heard from early Sunday when they uploaded a photo of a backpack. Pictured: Jonathan with baby Muji

“We know that John and Ellen’s family and friends are desperate for answers, our team of detectives is working around the clock,” Sheriff Jeremy Briese said in a statement. San Francisco Chronicle.

“Cases like these require us to be methodical and thorough, while also reaching out to any resources we can find to help us get those answers to them as quickly as possible.”

The family's dog, Oski, was found dead by search teams along with his owners

The family's dog, Oski, was found dead by search teams along with his owners

The family’s dog, Oski, was found dead by search teams along with his owners

Investigators first revealed that Gerrish was researching the Hites Cove walk on a phone app the day before the family left.

On August 15, around 7:45 a.m., a witness saw the family drive to the track in their truck.

At 11 p.m. on Aug. 16, a missing person was reported and a Mariposa County sheriff’s deputy discovered their truck about three hours later at the end of Hites Cove Road near the trailhead.

Search teams were deployed on the steep trails and the family was found at 11 a.m. on August 17 along the hairpin bends leading back to their trucks.

There was little evidence for detectives at the scene and no signs of malicious intent, police said.

Samples of water from the river, creek, and from a bladder-lined backpack remain in the lab awaiting results.

Further testing was conducted with the Centers for Disease Control and Prevention and the California Office of Environmental Health Hazard Assessment.

No significant evidence was found in searches of the family home and vehicles, the sheriff’s office said.

They were found on the Savage-Lundy Hiking Trail at Hites Cove, which was once a thriving mining community after gold was discovered in 1861.

Gerrish was a software developer for Snapchat, had previously worked for Google. He graduated from Newcastle University.

His American wife studied psychology and the couple was very active, often spending time outdoors or traveling.

Last month, Sierra National Forest officials posted a warning about “high concentrations” of algae that 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 area in Mariposa County, California, where the bodies were discovered Tuesday

This map shows the remote area in Mariposa County, California, where the bodies were discovered Tuesday

This map shows the remote area in Mariposa County, California, where the bodies were discovered Tuesday

County Sheriff Jeremy Briese said, “I’ve been here 20 years and I’ve never seen a death case like this. There are no clear clues as to how it happened.”

Officials had previously considered the possibility of gas escaping from abandoned gold mines.

But the sheriff said they couldn’t find any unused shafts nearby.

“We didn’t find any old mine shafts nearby,” he added. “There are some mine shafts, but we can’t confirm if that’s the cause yet.”

California State Water Resources Control Board and Mariposa County are now retesting river water for cyanobacterial toxins, which can form in algal blooms.

On July 13, Sierra National Forest officials posted a warning about “high concentrations” of algae that can produce “extremely dangerous toxins that can sicken or kill people and animals” in the water in the Merced River off Hites Cove.

Seekers began searching for the family Monday after they were reported missing by friends while failing to report to work

Seekers began searching for the family Monday after they were reported missing by friends while failing to report to work

Seekers began searching for the family Monday after they were reported missing by friends while failing to report to work

The area where the family's bodies were found was initially treated as a dangerous situation due to the strange circumstances

The area where the family's bodies were found was initially treated as a dangerous situation due to the strange circumstances

The area where the family’s bodies were found was initially treated as a dangerous situation due to the strange circumstances

Signs have been placed on the trail warning hikers of 'high levels' of algae that can produce 'extremely dangerous toxins that can sicken or kill people and animals' in the water in the Merced River at Hites Cove

Signs have been placed on the trail warning hikers of 'high levels' of algae that can produce 'extremely dangerous toxins that can sicken or kill people and animals' in the water in the Merced River at Hites Cove

Signs have been placed on the trail warning hikers of ‘high levels’ of algae that can produce ‘extremely dangerous toxins that can sicken or kill people and animals’ in the water in the Merced River at Hites Cove

The bodies were located near the Hite Cove trail, which is especially known for its spectacular wildflowers in the spring.

The bodies were located near the Hite Cove trail, which is especially known for its spectacular wildflowers in the spring.

The bodies were located near the Hite Cove trail, which is especially known for its spectacular wildflowers in the spring.

However, the California Department of Public Health said it was not aware of human deaths from “recreational or drinking water exposure to cyanobacterial toxin,” although some animals have been killed by algae.

The listing on the state map for the location north of Jerseydale, near where the family was found dead this week, is warning people to “stay away from algae and foam in the water.”

“DO NOT let pets enter the water, drink the water or eat dung on the coast,” the warning continues. ‘Keep children away from algae. Do not eat shellfish from this body of water.’

Investigations continue and it could take up to five weeks for toxicology reports to come back.

WHAT ARE THE RISKS OF ALGAE FLOWERS?

Cyanobacteria, also known as blue-green algae, are an ancient class of organisms that allow the flowers to be present almost anywhere water is found, but thrive in warm, quiet bodies such as lakes and ponds.

It includes species that produce some of the most potent toxins known to man, and their impact on humans is only partially understood.

The incidence of freshwater-damaging algal blooms (FHABs) has skyrocketed in recent years, with some scientists attributing the increase to climate change.

What are the health risks?

Algae can produce various toxins. Humans can be exposed to these toxins through skin contact (e.g. while swimming), inhalation (e.g. while motorboating or water skiing) or ingesting contaminated water.

These toxins can cause skin rashes, nausea, vomiting, stomach pain, fever, and headache.

Occasionally, the toxins can cause more serious illnesses, such as liver and brain damage.

Children are at greater risk than adults of developing problems because of their relatively lower body weight.

The California Department of Public Health says it has no known human deaths from “recreational or drinking water exposure to cyanobacterial toxin,” although some animals have been killed by algae.

How can the health risks be minimized?

Not all blue-green algae blooms and foams are poisonous, but it is not possible to tell by appearance and so it is best to assume they are harmful and take the following precautions:

  • Do not swim in the water
  • Do not swallow the water!
  • Avoid contact with the algae
  • Do not eat fish caught out of the water!
  • Please pay attention and follow all warnings posted around the water

Anyone who has come into contact with water containing algae should immediately shower with fresh water.

Anyone who has been in contact with contaminated water and has become ill should seek medical attention.

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