MARIPOSA, Calif. (NewsNation Now) — A desperate text for help sent by a family who later died on a hike on a California trail last year went undelivered, authorities said on Facebook Thursday.

Jonathan Gerrish, 45, Ellen Chung, 30, and their daughter, Aurelia “Miju” Chung, 1 and family dog Oski were found dead Aug.17 on the Savage Lundy Trail in Mariposa County.

Using information extracted from Gerrish’s phone, the Mariposa County Sheriff’s Department re-created the path and timeline of the family’s fatal hike based on GPS locations.

Because they didn’t have cell service in the area, a text sent asking for assistance was attempted, but never successfully delivered.

“(Name redacted) can you help us. On savage lundy trail heading back to Hites cove trail,” the text said. “No water or ver (over) heating with baby.”

Five calls, not including ones made to 911, were also attempted, but the calls were never connected.

“The cell phone data results were the last thing both the family and detectives were waiting on. The extracted information confirms our initial findings,” Mariposa County Sheriff Jeremy Briese said on Facebook. “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.”

The family’s cause of death, according to the sheriff’s office, was determined to be “hyperthermia and probable dehydration due to environmental exposure.” Oski’s cause of death is still undetermined.

On the trail, the family was exposed to sunlight with very little shade. Temperatures got between 107 and 109 degrees.

In the remote area where the bodies of the family were found, there was no cellphone service.

A report released last year found that the parents likely died trying to save Aurelia from the extreme heat. The report’s findings, which were first reported by the San Francisco Chronicle and obtained by NewsNation, shows that the baby died first, and the parents made several attempts to help the child that proved unsuccessful.

Authorities found Gerrish, the baby, and the dog’s bodies first. Chung was about 13 feet higher than them, in an apparent attempt to hike up the hill for help.

The family had apparently overestimated their water supply for the hike. On the morning they set out on the hike, the temperature was 76 degrees, but this swelled to a scorching 109 later that day.

Briese said they only had “a small amount” of formula and some snacks.

NewsNation affiliate station KSEE contributed to this report.