A woman hiking alone on the Crosier Mountain trail was found dead around 12:15 p.m. on Jan. 1 after nearby hikers saw a mountain lion near her body and drove it off with rocks, authorities said. State wildlife officers and Larimer County deputies searched steep timbered slopes through the afternoon, later euthanizing two mountain lions located near the scene as investigators documented tracks, collected samples and secured the area.
Officials said the setting and initial evidence were consistent with a mountain lion encounter, but the Larimer County coroner will determine the cause and manner of death after an autopsy. Colorado Parks and Wildlife, which is leading the wildlife component of the response, described the incident as rare and said euthanizing animals suspected of attacking a person is standard protocol to prevent further harm while evidence is gathered. The victim’s name had not been released by Friday pending family notification. The case has renewed public attention on lion activity in the foothills between Glen Haven and Estes Park at the start of a holiday weekend that drew heavy trail use.
Witnesses told responders they were on a remote segment of the Crosier Mountain network when they spotted a lion near a person lying on or just off the path shortly after noon on New Year’s Day. As they approached and threw rocks, the animal retreated. One hiker, a physician, checked for a pulse and found none, according to officials. Firefighters, sheriff’s deputies and Colorado Parks and Wildlife officers converged on access points along canyon roads and fanned out on foot. A lion seen lingering nearby was shot and fled into heavy cover; trackers and hounds later located the injured cat, which was euthanized. A second lion found in the vicinity was euthanized as a precaution. Crews staged at trailheads as a helicopter orbited to help spot movement in the forest while detectives photographed tracks and flagged a swath of ground for evidence.
Authorities said the woman appeared to be hiking alone and suffered injuries consistent with a wildlife encounter, but detailed descriptions were withheld as the death investigation proceeds. The agencies involved include Colorado Parks and Wildlife, the Larimer County Sheriff’s Office, Estes Park Police and local fire districts. Trail users were asked to avoid the immediate area Thursday while crews worked in rugged terrain between Glen Haven and Estes Park, a gateway to Rocky Mountain National Park. By late afternoon, responders had documented distances to intersections, gathered hair and scat samples and began a grid search for additional trace evidence. Officials emphasized there was no broader public safety threat once the perimeter was established, though closures were extended around the core scene during testing and necropsies.
Colorado estimates there are roughly 3,800 to 4,400 mountain lions in the state. Attacks on people are uncommon; officials count a few dozen reported incidents since 1990, most resulting in minor to moderate injuries. The last fatal case in Colorado dates to 1999, agency tallies show. The Crosier Mountain trail climbs through mixed ponderosa and Douglas fir with narrow benches and limited sight lines, conditions that can obscure wildlife at close range. Sightings near Glen Haven are not unusual in winter as deer drift into lower elevations. Residents said sirens echoed up the canyon on New Year’s Day and that crews rotated in and out of staging areas as darkness and a thin crust of snow set in. By nightfall, the parking lots were mostly empty as officers left the scene.
In the weeks before the suspected fatal attack, a local runner reported fending off a mountain lion on the same trail during a pre-dawn outing in November. Temporary warning signs went up after that encounter and were later removed. Officials said they are reviewing recent reports and will fold the new evidence into a seasonal update on wildlife-human interactions along the Front Range. Nearby land managers posted temporary closures for several trailheads while biologists and deputies searched for any additional lions tied to the incident. As of Friday morning, necropsies on the two euthanized cats and laboratory testing for human DNA, rabies and other pathogens were pending.
Procedurally, the Larimer County coroner will issue preliminary findings after the autopsy, which could take several days, followed by more definitive lab results. Wildlife veterinarians will swab claws and mouths from the euthanized lions and compare DNA to samples gathered at the scene. If tests do not match, officers said they could continue to look for another animal; if they do, the case file would move toward a final determination in Colorado Parks and Wildlife’s annual reporting. Trail closures will be reassessed as investigators complete documentation, and any broader management changes would be considered by state biologists in consultation with county and federal land managers.
Along the switchbacks above Glen Haven on Friday, strips of tape marked sections of trail where rangers logged measurements and photographed tracks. A resident watching trucks move through town said people were “quiet and worried” as word spread that a woman had died on a familiar route. Hikers who exited midafternoon described officers carrying evidence bags and walking the trail out in both directions. “Everyone got very still,” one said, recalling a ranger who accompanied them back to the lot. Wildlife officers said the sequence followed established steps for serious incidents: secure the scene, render aid, remove immediate threats, and preserve evidence for the coroner and the lab.
As of Saturday, the victim had not been publicly identified, and authorities were awaiting autopsy and DNA results. Temporary closures around Crosier Mountain remain in effect while crews finish documentation and complete necropsies. Officials said the next milestone will be the coroner’s preliminary report, expected in the coming days, followed by laboratory findings on the two lions.
Author note: Last updated January 3, 2026.