A married couple, their 1-year-old daughter, and their dog died under mysterious circumstances while hiking in Sierra National Forest in northern California. Authorities have ruled out suicide or murder, and they are now considering the possibility that they were exposed to toxic algae blooms.
People who knew Ellen Chung and her husband, John Gerrish, said the couple were experienced hikers.
"This is a very unusual, unique situation," Kristie Mitchell, a spokesperson for the sheriff's office, told NPR. "There were no signs of trauma, no obvious cause of death. There was no suicide note."
The area in the Sierra National Forest where the bodies were found on Tuesday had been treated as a hazmat site after concerns were raised about the deaths being linked to potentially toxic gases from old mines nearby.
But the hazmat declaration was lifted Wednesday, and Mariposa County Sheriff Jeremy Briese said he didn't believe the mines were a factor, the Fresno Bee reported Thursday.