Authorities believe that she walked west from Mather Point, a popular lookout, toward Bright Angel Lodge or Hermits Rest, the most western point of the South Rim of the Grand Canyon.

Authorities continue to search for a Sault Ste. Marie, Mich., woman reported missing at Grand Canyon National Park. National Park Service officials said 66-year-old Martha Anne Overholser was last seen at Mather Point on the canyon’s South Rim on Dec. 10 and later failed to return on a commercial bus tour.