A woman has died following a mountain lion attack south of Glen Haven in Larimer County, marking the first fatal mountain lion attack in Colorado since 1999.

According to Colorado Parks and Wildlife, a group of hikers encountered a mountain lion near a person lying on the ground yesterday afternoon. The hikers threw rocks at the animal in an effort to scare it away before approaching the woman to provide aid. One member of the group, who was a physician, attempted to assess her condition but did not find a pulse.

First responders and wildlife officials launched a search for mountain lions in the area following the incident. The operation concluded with two mountain lions being located and euthanized.

The woman’s identity has not yet been released. Authorities continue to investigate the circumstances surrounding the attack.