(NewsNation Now) — A new report found two California parents likely died trying to save their infant from extreme heat as the family was hiking in the Sierra National Forest.

The family was discovered dead after they disappeared on the hike in August. Some speculated a toxic algae bloom may have killed them, but this fall, investigators ruled they all died from hyperthermia.

The new findings, first reported by the San Francisco Chronicle and then obtained by NewsNation, reveal the baby likely died first and the parents made several attempts to help their child that proved unsuccessful.

John Gerrish, 45; Ellen Chung, 31; Miju Gerrish, 1; and the family dog were found dead Aug. 15.

The report says authorities first located the bodies of Gerrish, the baby and the dog. The mother was lying about 13 feet higher, apparently trying to hike up the hill for help. 

Authorities wrote the family was likely caught off guard while overestimating their water supply for their hike.

The morning of the hike, the temperature was 76 degrees, but swelled to a scorching 109 later that day. Mariposa County Sheriff Jeremy Briese said they only had “a small amount” of formula and some snacks.

One doctor told investigators that the “clock was ticking” the moment the family started the hike, the new report shows. No toxins were ever found in their drinking water and police found no evidence of foul play.

The family had a cellphone but there was no cell service. Authorities have not been able to gain access to the phone, however.