How did investigation into death of family hiking near Yosemite play out? A timeline

Mariposa County Sheriff Jeremy Briese gave a new conference on Thursday: the final update to a months-long investigation into the deaths of a family found along a hiking trail in the Sierra National Forest.

According to the update, which streamed live on Facebook, the official cause of death for John Gerrish, Ellen Chung, and their one-year old daughter, Miju, is hyperthermia and probably dehydration caused by the heat.

The death of the family’s dog Oski, was undetermined, but could also be a heat-related death, Briese told media on Thursday.

Prior to the update, there had been much speculation, but few details released about the mid-August deaths of Gerrish, Chung, Miju and the dog. Possible causes included everything from homicide to toxic gases and deadly algae blooms.

Here’s a timeline of events as the investigation unfolded.

• Saturday, Aug. 14: Jonathan Gerrish researches Hites Cove hike via a phone app.
• Sunday, Aug. 15: 7:45 a.m., witness sees the Gerrish/Chung family traveling in their vehicle toward the trailhead, down Hites Cove Road north of Jerseydale in Mariposa County.
• Monday, Aug. 16: 11 p.m., a family friend reports the family missing.
• Tuesday, Aug. 17: 1:53 a.m., the family’s car is located down Hites Cove Road north of Jerseydale.
• Tuesday, Aug. 17: 1:55 a.m., a search and rescue mission is initiated.
• Tuesday, Aug. 17: 11 a.m., the family is found dead on the Savage-Lundy Trail by a search and rescue team.
• Thursday, Aug. 19: Autopsies are completed on the family and dog. The autopsy findings state “pending toxicology” results.
• Friday, Aug. 20: Search warrants issued for a phone found with the family.
• Friday, Aug. 20: Search warrants issued for the family’s home and cars. “Nothing significant” is found.
• Monday, Aug. 23: Additional water samples are collected from water sources “along the trail area.” Other samples from that area were sent to a lab the previous week. There’s a known harmful algae bloom in the south fork of the Merced River, in the region where they were found.
• Tuesday, Aug. 24: A cell phone is delivered to the FBI for data extraction, “awaiting results.”
• Wednesday, Aug. 25: Search warrants issued for “possible social media access.”
• Thursday, Aug. 26: Sheriff’s office issues an update ruling out weapons and “chemical hazards” along the Savage-Lundy Trail. “All other potential causes of death remain.”
• Saturday, Aug 28: Sierra National Forest announces the closure of numerous hiking trails, picnic areas and campgrounds, citing “unknown hazards found in and near the Savage Lundy Trail,” where the family was found.
• Sunday, Sept. 26: The closure order is extended by the National Forest Service and now runs through Oct. 29.
• Thursday, Sept. 30: Interviews and tests are ongoing, according to an update from the sheriff’s office. Authorities officially rule out the use of a gun or any other type of weapon as cause of death; also lightning strike, carbon monoxide, carbon dioxide, cyanide exposure, illegal drugs, alcohol or suicide. All other causes of death remain possible.
• Wednesday, Oct. 20: The Sheriff’s Office announces its “final investigative update” about the case and the family’s “cause of death.”

This story was originally published October 21, 2021 at 1:48 PM with the headline "How did investigation into death of family hiking near Yosemite play out? A timeline."