A hiking trail in the Sierra National Forest where a family of three and their dog were found dead two weeks ago was shut down on Aug. 28 due to "unknown hazards found in and near the Savage Lundy Trail."

John Gerrish and Ellen Chung went hiking with their 1-year-old daughter, Miju, and their dog, Oski, on the Savage Lundy trail early in the morning on Aug. 15, a sweltering Sunday when temperatures reached as high as 109 degrees, according to the Mariposa County Sheriff's Office

When Gerrish didn't show up to his job as a software engineer on Monday, a friend reported them missing. The family was then found deceased on the trail about 1.5 miles from their vehicle on Tuesday, Aug. 17. 

There is no clear cause of death for the family and autopsies have failed to turn up any clues, though toxicology reports are still pending. 

Authorities have ruled out weapons and chemical hazards along the Savage Lundy trail as potentially causing their deaths, and a spokesperson for the sheriff's office said homicide is not being considered. 

"Initially, yes, when we come across a family with no apparent cause of death, there's no smoking gun, there's no suicide note, there's nothing like that, we have to consider all options," Kristie Mitchell, a spokeswoman for the Mariposa County Sheriff, previously told Fox News. "Now that we're five days in, no, we're no longer considering homicide as a cause of death."

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The closure order will be in effect through Sept. 26, or until "conditions change" at the trail. 

"As a precaution and to protect the public from unknown hazards in the area, The SNF decided to close several recreation sites, roads, and trails along the Merced River and its South Fork, until deemed safe for public use," the U.S. Forest Service said in an advisory. 

The Savage Lundy trail leads into the South Fork Merced River, which the Sierra National Forest has warned people against drinking from or swimming in due to potentially harmful algal blooms.  (Google Maps)

The Savage Lundy hiking trail where the family was found ends at the South Fork Merced River. 

The Sierra National Forest noted in its closure order that potentially harmful algal blooms (HABs) have been identified in the South Fork of the Merced River, and the California Department of Fish and Wildlife warned hikers in mid-July "not to swim, wade or allow their pets to enjoy the water" due to the toxic HABs. 

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The U.S. Forest Service announced on Aug. 30 that all National Forests in California will be shut down through Sept. 17 in order "to better provide public and firefighter safety due to the ongoing California wildfire crisis."

The area is the site of mid-19th century gold mines that are now abandoned and have the potential to emit toxic gases like carbon monoxide, but the sheriff's office told Fox News last week that it has ruled out carbon monoxide poisoning.