San Mateo County Parks staff on Tuesday evening discovered human remains at the San Bruno Mountain State and County Park.
The remains appear to have been there for a long time, according to Detective Rosemerry Blankswade, spokeswoman for the San Mateo County Sheriff's Office.
The Sheriff's Office on Wednesday posted about the discovery from its Twitter account, along with a video of Blankswade describing the situation as investigators worked at the scene.
Maintenance staff at the park found the bones near a high point of the mountain during routine park management, Blankswade said in an interview Thursday.
"We don't have any evidence that leads us to believe that there is foul play involved," she said. "But this is such an old scene that a lot of the evidence has probably diminished over time."
Detectives from the Sheriff's Office are working to investigate the case and determine the identity of the person, their cause of death and how long the bones could have been there.
As of Thursday, San Bruno Mountain State and County Park is closed to the public due to the ongoing investigation.
Anyone with information can call the sheriff's Detective Bureau at (650) 599-1536.