MARIPOSA, Calif. (NewsNation Now) —  It’s a tragic case that has many anxious for explanations and answers. With no major clues from the autopsies, officials must now wait for toxicology results to determine how a family of three and their pet dog died in the Sierra National Forest.

The mystery deaths of John Gerrish, Ellen Chung, their daughter, Miju, 1, and the family dog, Oski, remain a mystery one week after the family was reported missing. Their bodies were discovered the next day on a hiking trail.

The family enjoyed hiking and had recently moved to Mariposa from the Bay Area.

“Think a great way to describe them would be universal friends because they just made everybody feel comfortable around them,” said Noelle Stobbe, a Mariposa restaurant worker. “They were just genuine people.”

The autopsies confirmed no signs of trauma and initial suspicion about toxic gases from old mining shafts has shifted to toxic algae blooms in the Merced River.

The U.S. Forest Service had issued an alert just last month and there was said to be signage on the trail warning hikers not to swim, wade or allow pets to enjoy the water.

Algae is not uncommon during the summer months all over the country, so warnings about the health threat are posted in many areas.

In many instances, they are ignored.

“It’s pretty rare for these algae toxins to actually kill people, but it can happen,” said Anne Schechinger, a senior analyst with Environmental Working Group. “And every year, many dogs and livestock and other animals, wildlife, geese and birds, are killed in the United States because of exposure to these toxins from algae blooms.”

The toxicology results will likely be key in learning the cause of deaths of the family. The Sheriff’s Office expects those results back in the next few weeks.

Water from the Merced River is also being retested.