Jonathan Gerrish, Ellen Chung and their 1-year-old daughter, Miju, died of hyperthermia, the condition of having a high body temperature, with possible dehydration from environmental exposure.
After several months of investigation with the FBI, the Mariposa County Sheriff’s Office extracted data from Gerrish’s cell phone, allowing them to trace the family’s last steps.
Authorities were able to extract a text from Gerrish’s phone at 11:56 a.m. asking for help. He was never received due to lack of cell service in the area.
“Can you help us,” the text reads. “On the Lundy wilderness trail back to the Hites creek trail. No water or heater (over)heated with baby.”
About 13 minutes after the text message failed, Gerrish’s phone showed that he had tried calling several numbers, not including 911, but again, due to a lack of service, the calls did not go through. are never connected, authorities said.
The first call was made at 12:09 p.m. after four subsequent calls at 12:35 p.m. less than a minute apart.
In addition to the text messages and phone calls, authorities released nearly 16 photos from Gerrish’s camera roll.
The first photo was a photo taken a few feet from the trailhead around 7:44 a.m. on the morning of the family hike, followed by 16 more photos including family selfies, photos of the river and creek, and ending with a capture of screen of their location from a trail app at 12:25 p.m.
At around 7:45 a.m., a witness walking in the area saw the family truck heading toward the Hite Cove Trail Head, authorities said. At 8 a.m., the witness saw the truck parked at the trailhead and no family around.
The approximate temperature was 74 to 76 degrees, at an elevation of 3,880 feet.
The family was reported missing the following day after the family’s babysitter arrived for her normal shift, but could not locate Gerrish, Chung or their daughter, authorities said.
On August 17, search and rescue teams found the family dead 2.5 km from their car on the Savage Lundy Trail. An empty 85 ounce water pack was with them.
At the intersection of the Savage Lundy trail, the elevation is about 1800 feet and the temperature throughout the trail ranged between 107 and 109 degrees, cooling slightly in the evening. This section of the trail is a south/southeast facing slope, so it is exposed to constant sunlight.
The family dog, Oski, was also with them and authorities believe he was also suffering from heat-related issues.
CNN’s Sarah Moon contributed to this report.