Nearly two months after a couple, their infant child, and their dog were found dead in a remote section of the Sierra National Forest near Yosemite National Park, investigators still aren’t sure what killed them.
Husband and wife Jonathan Gerrish and Ellen Chung were discovered by search teams on August 17, 2021, along with their 1-year-old daughter, Miju, and their dog, an Aussie-Akita mix named Oski. They exhibited no signs of external trauma, and investigators have been unable to confirm death from heat stroke or internal injury. The family was discovered near Devil's Gulch along the South Fork of the Merced River in Central California about 100 miles east of Modesto.
Most recently, on September 30, the Mariposa County Sheriff’s Office released a statement on Facebook ruling out several potential causes and begging the public for more time to complete their work.
“We respect and understand the need for information and details regarding this case,” said Sheriff Jeremy Briese. “Our current priorities remain supporting and informing the Gerrish/Chung family during this tragic time. As we navigate through this investigation with the family, we will later share our findings with the public."
The cause of death remains undetermined, the statement said, though investigators are still waiting for the results of additional toxicology reports. They did not release a timeline for those pending results and did not respond to multiple requests for comment.
They did, however, rule out several causes of death that had been proposed by media and members of the public. Gerrish and his family were not killed by lightning strike, carbon monoxide, carbon dioxide, cyanide exposure, illegal drugs, alcohol, or suicide.
Heat Stroke With temperatures hovering near 100 degrees Fahrenheit on the day of the family’s disappearance, it’s easy to assume that Gerrish, Chung, and their daughter succumbed to heat exhaustion.
But the New York Times interviewed a friend of the couple who described them as “experienced hikers” who had backpacked in the Himalayas and ridden camels through the Gobi Desert, among other excursions.
The Fresno Bee reported that the Savage/Lundy Trail where the family was found is “rugged and remote” but still a popular destination for hikers in the area. Sheriff Briese told The Bee the family had hiked about 1.5 miles away from their vehicle.
Even if the family forgot to bring water, it’s unclear how two experienced hikers could have died from the heat without sustaining any apparent injuries.
Still, the Mariposa County Sheriff’s Office has not ruled out any causes of death not listed in their statement. Heat-related deaths are difficult to diagnose post-mortem, according to a 2012 article published in the International Journal of Legal Medicine.
“The diagnosis of hyperthermia is therefore essentially based on scene investigation, the circumstances of death, and the reasonable exclusion of other causes of death,” the article states.
Abandoned Mines In the absence of any obvious physical evidence, investigators and the public hypothesized that the family could have died from invisible agents. Carbon monoxide, carbon dioxide, and cyanide were the first on the list. However, Briese told The Bee that the only mine he’s aware of in that area is at the bottom of Hites Cove, and that’s about 2.75 miles from where the family was found.
Abandoned mines can contain cyanide, arsenic, mercury, and other deadly toxins along with lethal concentrations of methane, carbon monoxide, carbon dioxide, and hydrogen sulfide that may accumulate in underground passages, according to the Wyoming Department of Environmental Quality.
While investigators have not publicly ruled out all types of harmful gasses and chemicals, they have ruled out carbon monoxide, carbon dioxide, and cyanide. In addition, the family was found above ground in the open air a long way from the nearest mine.
Water, Algae, and Park Closures Some have also hypothesized that the family died of poisoning from toxic algae in the Merced River.
The New York Times reported that on August 19, two days after the family was found, that the California State Water Resources Control Board warned the public to “stay away from algae and scum in the water” near the South Fork of the Merced River in the Sierra National Forest.
“Do NOT let pets go in the water, drink the water, or eat scum on the shore,” the warning said. “Keep children away from algae. Do not eat shellfish from this waterbody.”
The water quality map used by the Control Board reports the incident in the same location as the family died.
“Algal mat samples were collected on 8/19 from the South Fork of the Merced River. Multiple types of cyanobacteria were detected,” the warning stated. “Anatoxin-a was detected at 11.8 ug/L, no other cyanotoxins were detected.”
The agency initially said they had received a report of a fatality but later changed it to a “suspected illness,” according to The Bee.
Nine days later, on August 28, the Forest Service announced a closure of all the trailheads and recreation sites near where the family was found, including the Savage/Lundy Trailhead.
The purpose of the order was to “provide for public safety due to unknown hazards found in and near the Savage/Lundy Trail, within the Bass Lake Ranger District,” the USFS said. On September 26, the Forest Service renewed those closures.
MeatEater reached out to the Forest Service for additional clarification but did not immediately receive a response.
According to the Minnesota Department of Health, anatoxin-a attacks the nervous system. Swallowing water with high levels of the toxin has caused death in lab animals, wildlife, livestock, and dogs within minutes to a few hours after exposure.
“In the spring of 2015, anatoxin-a was confirmed to be the cause of death for a dog who died after spending a short time in a Minnesota lake that had algal blooms,” the agency reports.
However, the MDH admits there is limited information about how anatoxin-a affects humans, and a similar argument could be made against the toxic algae theory that was made against the heat stroke theory: Why would two people with experience in the outdoors drink unfiltered stream water and give it to their infant?
A Tragic Reminder Friends and relations of the family are no doubt anxious to know the results of the final toxicology reports. Hopefully, those reports will contain the answers they’re looking for, and the Forest Service will be able to determine how to make sure no other hikers are threatened by whatever killed Gerrish, Chung, and their daughter.
Feature image via David Illif.
