Sierra
© Noah Berger/AP@dani_anguianoSearch crews found the family's vehicle near a gate to the Sierra national forest, above.
Investigators were searching for clues in the unexplained deaths of a California couple, their baby and the family dog in a remote area of the Sierra national forest.

John Gerrish, his wife, Ellen Chung, their one-year-old daughter, Muji, and their dog were found dead on a hiking trail in Mariposa county. A family friend had reported them missing Monday evening.

Search crews had located the family's vehicle near a gate to the Sierra national forest on Tuesday, and found the bodies of the family and the dog a little more than a mile away. The remote area had no cellphone service.

The cause of the family's deaths remained unclear on Thursday. "We haven't ruled anything out yet," Kristie Mitchell, a spokesperson with the Mariposa county sheriff's office, told the Guardian.

The area where the family was found was briefly treated as a hazmat site on Wednesday. Investigators were exploring whether carbon monoxide, exposure to gas from mines in the area or toxic algae could have been responsible for the tragedy.

The Mariposa real estate agent Sidney Radanovich, a friend of the family, told the San Francisco Chronicle that Gerrish was a San Francisco-based software designer who "fell in love with the Mariposa area" and bought several homes there.

The Gerrishes were avid hikers. "They were such a loving couple, they loved each other quite a bit," Radanovich told the newspaper.