Question

what in the story suggest the fact that the hat in front of holmes was under scrutiny?

The Blue Carbuncle
Arthur Conan Doyle​

Answer 1

Answer

A card addressed to Mrs Henry Baker had been attached to the bird, and the fact that the initials HB were imprinted on the brim of the hat, suggested that the hat belonged to Mr Henry Baker.

Answer 2

Explanation:

A car addressed to Mrs Henry Baker and had been attached to the bird.