OK, I just found it! It was a 1981 TV movie called
Dark Night of the Scarecrow about a retarded man who is unjustly accused of attacking a young girl. Disguised as a scarecrow, he hides in a cornfield, only to be hunted down and shot. Later, after it is revealed he saved the girl from a vicious dog attack, members of the search posse are killed by a mysterious scarecrow
http://www.imdb.com/title/tt0082235/#comment
