Phone records reveal tragic, final moments of Lancashire man and his family who died on US hiking trail

Police in the US have shared the desperate last calls and text messages - which were never received due to a weak signal - sent by Jonathan Gerrish, 45, who died along with his American wife Ellen Chung, 31, and their 1-year-old daughter, Miju, in the California wilderness last August.

They were reported missing the day after they ventured into the Sierra National Forest near Yosemite, where search-and-rescue teams discovered their bodies and that of the family dog Oski on a trail about 1.6 miles from their car in Devil's Gulch Valley.

But US authorities were unable to explain their deaths for more than two months, with a number of causes considered but ruled out, including carbon monoxide poisoning, exposure to gas from former gold mines, a lightning strike, suicide and drugs.

Their unexplained deaths puzzled FBI investigators until late October that year, when they finally concluded that the young family had been killed by hyperthermia and a lack of water after succumbing to extreme heat in the isolated Gold Rush region.

Temperatures on the day of their hike rose above 109F (42C), said police, who added that the family had been found with an empty 85oz (2.5-litre) water bladder and did not have any other bottles or water filters with them.

New information retrieved from Mr Gerrish's phone has allowed US authorities to re-create the family's tragic, final moments.

GPS data and pictures on their phones helped retrace their final footsteps, whilst unsent text messages and emergency phone calls that failed to connect show their desperate efforts for help in their last hours.

The couple attempted at least six phone calls and messages, but none of these reached emergency services because of poor phone reception in the remote Sierra Nevada mountains.

In one tragic, unsent message, Gerrish, who was from Lancaster and has family in Bamber Bridge, wrote: "Can you help us. On savage lundy trail heading back to Hites cove trail. No water [over] heating with baby."

About 13 minutes later, Gerrish's phone showed that he tried calling multiple numbers, not including 911, but again, due to lack of service, the calls never connected.

Speaking on Thursday (February 17), the Mariposa County Sheriff's Office said: "Using the information extracted from the phone we were able to re-create the path and timeline based on the GPS locations.

"The details found on the phone support the findings of a heat-related incident."

A US Forest Service volunteer, who was one of the last to see the family alive, told authorities that the family appeared “completely unaware of the dangers”.

Police records revealed the couple only carried a 'sippy cup' and a backpack with a 2.5-liter reservoir for water. The temperatures were around 25c during the morning and quickly rose to (43c) in the afternoon while they were on the trail.

In Thursday’s statement, Sheriff Jeremy Briese said: "The cell phone data results were the last thing both the family and detectives were waiting on. The extracted information confirms our initial findings.

"I am very proud of my team and our partner agencies for all the work they put in. Their dedication has allowed us to close this case and answer lingering questions the family had, bringing them a little peace."