Authorities are searching for a 39-year-old resident of the Helena Prerelease Center who walked away on Sunday.
Lionel Shepherd is described as a Native American man, 6 feet two inches tall and 185 pounds with a large build. He has black hair and brown eyes and tattoos on his neck.
He was in the center on a conviction of driving under the influence of drugs or alcohol.
Anyone with information on Shepherd's whereabouts is asked to call 911.