You had better go out as you came in.

It's better that no one up here should suspect anything." The voices ceased.
What did it mean! Constance rose and sauntered around into the next room.

It was empty, but when she looked hastily up on the shelf there was a bottle of white tablets and on a table a pad of note paper from which a sheet had been torn.
She picked up the bottle gingerly.

Who had touched it?
Her mind was working quickly.

Somewhere she had read of finger prints and the subject had interested her because the system had been introduced in banks and she saw that it was going to become more and more important.
But how did they get them in a case like this?
She had read of some powder that adhered to the marks left by the sweat glands of the fingers.