Mary Barton

In the short story The Companion, Miss Mary Barton is an Englishwoman. She had travelled to Gran Canaria with her companion Miss Durrant.

Some time after that Miss Durrant had drowned, Miss Barton herself drowned off the Cornish coast. Her body was never found, and she left a suicide note. In this note she confessed to the murder of her companion.

Miss Marple deducted that the woman who had drowned in Gran Canaria, actually was Miss Barton. Miss Durrant pretended to be Mary, and faked "Mary's" suicide in Cornwall.