Fast food staff threatened

A man threatened staff smashed a window at a fast food restaurant in Cooloongup overnight.

Police said the man approached the drive-thru window on foot and became aggressive after he was refused service.

He punched the window and threatened staff, before walking to the front doors, which were locked, and punching a window, causing it to smash.

Police dog Ernie tracked the man to a nearby park.

A 22-year-old Cooloongup man has been charged with criminal damage and will appear in Rockingham Magistrates Court on February 13.