GILLETTE, Wyo. (AP) — More than 50 people have been searching the area northwest of Gillette for a mother of three who has been missing since Monday.

Authorities say 49-year-old Ruth Martinson was last seen after she left a class at Gillette College on Monday afternoon. She was driving her black Toyota Tundra pickup truck with the license plate 17-17542.

The Gillette News-Record reports ( Martinson was wearing a pink, purple and black Harley-Davidson sweat shirt.

Her daughters say she wouldn't have left town without telling them.

Volunteers drove around and handed out flyers with Martinson's picture on it Wednesday. Relatives say they are widening the area they are searching.

Anyone with information can call Gillette police at (307) 682-5155.