
Detectives have ruled out more causes in the mysterious deaths of a Mariposa family last month at Sierra National Park, but the case remains unsolved.
Forty-five-year-old John Gerrish, 31-year-old Ellen Chung, their one-year-old daughter Miju and their dog were discovered dead on Aug. 17 at a remote hiking trail 15 miles southwest of the entrance to Yosemite National Park.

The case has baffled investigators in the weeks since, as the bodies showed no signs of trauma. A spokesperson for the Mariposa County Sheriff's Office previously called it "a very unusual, unique situation."
Authorities said Thursday that the investigation remains ongoing, however they have ruled out the following causes of death: gun or any other type of weapon, lightning strike, carbon monoxide, carbon dioxide, cyanide exposure, illegal drugs/alcohol, and suicide.
The only remaining possibilities that the sheriff's office has publicly discussed are heat exposure and toxic algae.
Officials previously said temperatures the afternoon of the hike ranged between 107 and 109 degrees.
Detectives are continuing to conduct interviews and investigate all other possible explanations. While most toxicology reports have been completed, there are still "key results" pending and no timetable for when those will be completed.
The sheriff's office is working closely with toxicologists, environmental specialists, the FBI, among others during the investigation.
"We respect and understand the need for information and details regarding this case," Sheriff Jeremy Briese said. "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 family was originally from San Francisco but moved to Mariposa County during the coronavirus pandemic.