A family of 3 who mysteriously died on a hike tried calling and texting for help, saying they had no water and were overheating with their baby

• A family on a day hike in California in August was found dead with no apparent cause of death.
• Two months later, officials said the family had died of extreme heat and dehydration.

Police released new details Thursday about a family of three who died of extreme heat and dehydration while hiking in Northern California over the summer, a case that initially mystified officials.

The bodies of John Gerrish, Ellen Chung, their 1-year-old daughter, Miju, and their dog, Oski, were found in Sierra National Forest on August 17. The Mariposa County Sheriff's Office said at the time that there was no clear cause of death. Two months later, officials said the family had died of "hyperthermia," or the overheating of the body, and "probable dehydration."

In a statement provided to Insider on Thursday, the sheriff's department released phone records from the hike, including attempted calls and photo time stamps, that showed the family realized they were in danger and tried calling for help.

On the morning of the hike, estimated temperatures were about 76 degrees Fahrenheit at the parking area where they left their car and set off on foot. After hiking about 4 miles, the family reached an area where temperatures exceeded 100 degrees before continuing on to a steep section of trail that had no shade.

The first photo noted by police was taken near the trailhead at 7:44 a.m. The couple continued to periodically take photos, including family selfies about 10 a.m. and a photo of a creek about 10:30 a.m., according to police.

The first signal of distress in their phone records came at 11:56 a.m., when they tried sending a text for help. Because of a lack of cell service, the text never sent.

"Can you help us," the text said, according to police. "On savage lundy trail heading back to Hites cove trail. No water or ver (over) heating with baby."

They also tried making a call at 12:09 p.m. and four more calls back-to-back starting at 12:35 a.m., but none of the calls went through. Police said the couple did not try calling 911.

All cellphones can call 911, even without service or if the phone is not enrolled in a wireless plan. But in such cases, the caller's location will not be delivered to the 911 call center, and if the call is disconnected, the call center will not be able to call back.

The call attempts were made near where the bodies were found, about 1.6 miles away from where their car was parked. The family had hiked about 6 miles of the loop trail.

"The cell phone data results were the last thing both the family and detectives were waiting on. The extracted information confirms our initial findings," Sheriff Jeremy Briese of the Mariposa County Sheriff's Office said in the statement.

A survival expert previously told Insider that deaths and injuries related to extreme heat and dehydration were more common than many people realized.

"Their deaths are truly a tragedy," Cat Bigney, who has consulted for Bear Grylls and National Geographic, said. "Unfortunately, it happens every year to unprepared adventurers."