vivienne garton , 65 , was devastated after her west highland terrier ben was stolen .
she began an appeal to find him and put up posters near her home , but shortly after she received two phone calls from an anonymous man threatening to cut up the dog .
the caller gave the address of an empty house in bristol and a phone number which she handed to police , who are now investigating .
mrs garton , who lives with her husband and grandchildren aged between eight and 18 , says a number of her posters have now been ripped down .