MERCED (CBS SF) — Federal park officials ordered the closure of a trail in Mariposa County Sunday where the bodies of a family and their dog were discovered dead from unknown causes earlier this month.

Since Sunday, several recreational sites and trailheads around the Savage Lundy Trail in the Sierra National Forest were closed for a month “to provide for public safety,” according to the park service order. Per the order, anyone using or being anywhere near the listed trailheads could be subject to fines up to $5,000, or $10,000 if they are a group.

READ MORE: Repairs Finish Early on Ramp Between I-80 and Highway 101

The announcement came as investigators continue looking into what killed John Gerrish, his wife Ellen Chung, their 1-year-old daughter Miju and their dog back in mid-August. Their bodies were found on a hiking trail near Hite’s Cove on Aug. 17.

Family Found Dead in Sierra Nat'l Forest

John Gerrish, his wife, Ellen Chung, their 1-year-old daughter, Miju, and their dog were all found dead on a hiking trail near Hite’s Cove in the Sierra National Forest. (CBS Fresno via YouTube)

READ MORE: San Francisco Family Found Dead in Sierra Foothills, Possible Victims of Toxic Algae

READ MORE: Two Men Fatally Shot Near Laurel District in Oakland

Investigators said this week that they were still unsure of what killed the family. Last week they ruled out that possible gases from a nearby mine could’ve been the culprit, but there’s concern it’s still a hazardous site.

“This is a very unusual, unique situation,” Kristie Mitchell, a spokesperson for the sheriff’s office, said last week. “There were no signs of trauma, no obvious cause of death. There was no suicide note.”

Gerrish was a British expat turned San Francisco software designer who, with his wife, “fell in love with the Mariposa area” and bought several homes there, a residence for themselves and rental investments over the last few years.

MORE NEWS: Afghan American Family Finally Returns to California; 'It's A Story Of Hope'

The trails will stay closed until Sept. 26, though that is subject to change.