I like your story. Since I am not a teacher, I won't mention anything in regards to English structure.
I am the one who loves to write but not English... for sure! I think you can extend your story. I feel like it is very short. It might be because you wrote it in English, right?
You can add more plot points and character points into it so it could be more mysterious. You're gonna be the next Agatha Christie!
Student or Learner