Missing/Endangered Person Advisory issued for Sheridan County man MTN and last updated 2021-07-27 00:33:10-04 GREAT FALLS â The Montana Department of Justice on Monday evening issued a Missing/Endangered Person Advisory for Kevin Olson at the request of the Sheridan County Sheriff's Office. Kevin left Plentywood in northeastern Montana for a motorcycle trip to the South Dakota Black Hills area on Saturday and has not been heard from since. He is driving a blue 2008 Honda motorcycle. Kevin takes medication for a heart condition and there is concern for his health and safety. Kevin is 53 years old, 5 foot 9, 185 pounds, with grey hair and blue eyes.