BOULDER, Colo. (AP) — Colorado authorities are investigating a skull and other human remains discovered by hikers.

The Boulder County Sheriff's Office says hikers reported finding the skull on Monday near Lefthand Reservoir in the Brainard Lake Recreation Area.

Authorities searched the area on Tuesday and found the skull along with additional remains.

Authorities say the county coroner's office is working to identify the remains. No other information about the case has been released.