Is ‘The Open Window’ a mystery story? Give a reason for your answer.

‘The Open Window’ appears to be a mystery story due to the following reasons:

1. The window used to stay open.
2. Mrs. Sappleton awaited the return of her dead husband and brothers.
3. Mr. Nuttle saw three figures come inside through the window.
4. At the end of the story many questions remain unanswered making the story mysterious and complicated.