When Miss Trelawny had read her letter through, I had in my mind a conviction, which, however, I kept locked in my own heart.

Amongst the suspicions in the mind of the Detective was one, rather perhaps potential than definite, of Miss Trelawny herself.
For several minutes Miss Trelawny held the letter in her hand with her eyes downcast, thinking.

Then she read it carefully again; this time the varying expressions were intensified, and I thought I could easily follow them.

When she had finished the second reading, she paused again.

Then, though with some reluctance, she handed the letter to the Detective.