LA PLATA COUNTY, Colo. (KDVR) — The La Plata County Sheriff’s Office says human skeletal remains were found in southwest Colorado earlier this week.

The sheriff’s office, along with the Colorado Bureau of Investigation, responded to Middle Mountain Road near the Vallecito Reservoir on Monday after hikers in the area discovered the remains.

The CBI said the unidentified remains appear to be of an adult.

After the identity of the remains is determined, the coroner’s office will share them with the person’s next of kin.

The CBI and sheriff’s office said this is an active investigation.