The bodies of Jonathan Gerrish, 45, Ellen Chung, 31, and one-year-old Muji were found on Tuesday on a California hiking trail - with detectives admiting they had "never seen a case like this before". All three were discovered by a search team in a region of the 1.3 million square acre Sierra National Forest known as Devil's Gulch, along with their pet dog, who was also dead.

       Initially, authorities treated the remote site as a hazmat scene because investigators were unable to rule out the possibiity they had been overcome by carbon monoxide fumes from abandoned mines nearby.

       However, police have now confirmed the deaths are being treated as homicide.

       Mariposa County Sheriff Jeremy Briese said: "I've been here for 20 years, and I've never seen a death-related case like this.

       "There's no obvious indicators of how it occurred.

       "You have two healthy adults, you have a healthy child and what appears to be a healthy canine all within a general same area.

       "So right now, we're treating the coroner investigation as a homicide until we can establish the cause."

       Mr Briese said police could not find any disused shafts in the vicinity.

       He explained: "There are some mine shafts, but we can't confirm if that's the cause yet.

       JUST IN: POLL - has Joe Biden treated the UK with contempt?

       Mr Gerrish had only moved to the area recently San Francisco, and had been hoping to raise their child in "a quiet, slow-paced environment, surrounded by open-air and close to the mountains for hiking and camping adventures".

       He previously worked for Google but was employed by Snapchat at the time of his death.

       The family was supposed to be on a day trip - but when the nanny arrived at their house and found nobody home, she raised the alarm.

       Friend Steve Jaffe said: "You had to figure it wasn't an overnight hike because it's been hot, and they had the baby with them.

       DON'T MISS

       Afghanistan LIVE: Johnson makes urgent plea to save trapped Britons [WORLD]

       When you will have to self isolate as rules change for double jabbed [UK]

       BBC viewers 'switch off' as they slam Team GB Homecoming Concert [TV]

       "Jon was supposed to work Monday and never showed up. That raised more concerns."

       He added: "We're all just devastated. They were really beloved by the people.

       "A super generous, sweet and loving couple that was devoted to their daughter.

       "It's just a tragedy. You have people who pass away and die. And that's always sad.

       "This one is just so freaky and strange, and it's really, really sad. They had so much going for them.

       "They were doting parents. For this to happen to them and to their baby girl, it's exceedingly tragic."

       Newcastle University graduate Mr Gerrish was originally from Lancashire, while Ms Chung was from Orange Country in California.