‘Not one clue’: The mystery is only deepening around family found dead on a Sierra trail

MARIPOSA — When the missing persons report for Ellen Chung and her husband, Jonathan Gerrish, came in at 11 p.m. Monday, a curious sheriff’s deputy had a hunch. The couple had just purchased a property near the trailhead for Hites Cove Trail 20 miles north of town, and they loved to explore the outdoors with their 1-yearold daughter, Miju, and dog Oski.

He drove down the single-lane red dirt Hites Cove Road until the closed U.S. Forest Service gate appeared. He was right — the couple’s truck was parked at the popular but remote trailhead.

It was 2 a.m.

He called in backup, and nine hours later a searchand-rescue team made the grim discovery. The father, mother, baby and dog were all dead, about 1 1/2 miles below their truck on a series of switchbacks, appearing to be near the end of their hike. The family had been found, but the investigation was just beginning, and the mystery was only deepening in the booming foothills community that has seen an onslaught of new residents as city dwellers flee urban areas during the pandemic.

“You come on scene and everyone is deceased. There’s no bullet holes, no bottle of medicine, not one clue,” Mariposa County Sheriff Jeremy Briese said from his office in town on Friday. “It’s a big mystery.”

Autopsy reports for the family and dog remained outstanding Friday, with officials saying they don’t expect any definitive answers until lab technicians in Stanislaus County and UC Davis work through toxicology reports. There are no other obvious signs of trauma or notes indicating troubles. Authorities are investigating deadly gas exposure from unknown mines, toxic bacteria blooms in the waterways and basic dehydration — it was 107 to 109 degrees Sunday afternoon when officials believe they hiked.

Nothing yet has made sense, and any semblance of foul play seems far-fetched, Briese said. This was a young, energetic family — Chung was 31 and Gerrish 45 — who had left their San Francisco apartment to start a life working remotely and raising their daughter in the wilderness they loved.

“From everyone we talk to they were extremely happy, outgoing and loved finding Mariposa, and they were able to work from home and enjoy nature, and in the short time they were here they made a lot of friends,” said Briese, who was born and raised in Mariposa.

On Friday, under smoky skies, tourists on their way to Yosemite National Park passed along Highway 49, a two-lane road cutting through the downtown. A woman hung a handmade “Let’s Go Grizzlies” poster in the window of the Mother Lode Lodge, a nod to the Mariposa County High football game that night.

Patti Murdock owns Donuts A Go-go along the main drag. The 58-year-old left her tech job in the South Bay almost two decades ago and moved to Mariposa, where she could afford a ranch for her horses.

“They’re so young, those people — something’s weird,” Murdock said, standing behind her tray of glazed doughnuts. “Everyone is shocked. This is a very safe town. It’s like Mayberry up here.”

She recognized the photo of Chung in the news and said the young mother had stopped in a few times to pick up gluten-free and sugar-free doughnuts.

“I remember her cute baby,” she said.

Despite the sleepy vibe, Mariposa and the Hites Cove Trail have a dark side, she said. One of her regulars, calls it the “Mariposa Bermuda Triangle.”

Three years ago when the Ferguson Fire swept through the valley, burning more than 96,000 acres, a firefighter rolled his dozer down a ravine along the Hites Cove Road stretch of the trail and died. The north side of the trail empties out onto Highway 140 and the Yosemite Cedar Lodge, a notorious landmark.

In 1999, serial killer Cary Stayner was working as a handyman at the motel when he murdered 42-yearold Carole Sund; her daughter, 15-year-old Juli Sund; Juli’s friend, 16-year-old Argentine exchange student Silvina Pelosso; and Yosemite Institute employee Joie Ruth Armstrong. Sund and the teens had been staying at the motel.

In the latest tragedy, authorities believe the family left for their hike Sunday afternoon. The last known communication was with a friend earlier that morning.

When the deputy found the truck, a search-andrescue team hiked down the steep and straight road with flashlights and found shoe and paw prints similar to what you’d expect from a family of that size with a dog, Briese said.

At 3:20 a.m., the sheriff’s office reserved a search helicopter for daybreak. They called in a second search team that began winding down the switchbacks that complete the loop back up to the Forest Service gate. This section of the Hites Cove Trail makes a loop, with the halfway point the south fork of the Merced River.

About 1.5 miles down the switchbacks, around 11 a.m. Tuesday, the team found the family in the middle of the trail. The husband was in a seated position, the child beside him along with the dog, and the wife just a little farther up the hill. Briese said they believe the family was returning to their truck.

A cell phone was in Gerrish’s pocket. There is little to no cell coverage on that section of trail. Investigators are trying to determine if the phone saved any failed text message drafts, attempted calls or photos, along with GPS location data, Briese said.

The family also had a backpack with a bladder that held a small amount of water, the sheriff said. They sent the water for testing. There was no indication whether the family had been swimming, as they would have dried off by the time they were found, he said.

Two deputies slept near the family that night to ensure that no one tampered with the scene. The family was airlifted off the trail the next morning by a CHP helicopter.

Briese said they are investigating all possibilities to start eliminating options. While temperatures were scorching Sunday afternoon, dehydration seemed like a long shot, with their pet dying and the camelback still containing water. On Friday, investigators combed the lower section of the trail for unreported mines, but experts said it likely would take an exposure inside a mine shaft to kill a family. Investigators also took samples of bacteria blooms along the south fork of the Merced River and Snyder Creek, which run adjacent to the trail. Briese said they would also test for any other possible contamination in the water.

There have been few, if any, reports of human deaths linked to freshwater bacteria blooms. University of Southern California biological sciences Professor David Caron, who specializes in such proliferations, called them a “threat to both animals and humans.”

“Freshwater is a little more of the Wild West,” Caron said. “This is something that’s come onto our radar in the last five, six, seven years.”

The most common type in California is cyanobacteria. The one most connected to dog deaths is Anatoxin-a, also known as very fast death factor, a dangerous neurotoxin. The mass usually floats to the surface and creates bluegreen scums in a river environment, especially in eddies. It can be fatal if the dog drinks the water.

“Dogs can go downhill pretty quickly,” Caron said. “With a high enough toxin, you can have a rapid death if you’re exposed to enough of it.”

Could they kill humans rapidly?

“It’s conceivable that it is the cause,” Caron said. “But a lot needs to be done forensically to tie it to toxins. ... The question is if in the area there’s high enough concentrations.”

These types of bacteria blooms occur when nutrients in the ecosystem, such as nitrogen and phosphorus, build up. That is caused by humans, he said, as fertilizer and other chemicals seep into water systems. Drought and climate change exacerbate that process.

“The bacteria likes water warm and stagnant,” he said. “You slow water down and warm it up, it gives bacteria a competitive advantage.”

Fernanda Bray spends most Mondays over the summer hiking down to the south fork of the Merced River, on the northern end of Hites Cove Trail, along Highway 140, swimming, fishing and playing with her husband and two sons. She was alarmed when she heard law enforcement was probing whether that waterway played a role in the mysterious deaths.

“That could’ve easily been us,” said Bray, standing at the cash register of her Mariposa decor shop, Barnhoppers.

On Thursday, in a neighborhood near where the family’s truck was found, a Chronicle reporter ran into a man who identified himself as Chung’s brother. He cried as he explained how difficult the past 48 hours had been for his family. He said the family was not ready to speak about the tragedy and asked for privacy.

Sitting in his office, Briese said he has asked for the toxicology results to be expedited. His staff is working around the clock to find answers for the family. It gnaws at him.

“You have a healthy family, and it’s a tragic loss of a child and the entire family and there’s no real answers,” he said.