"On the second floor at the back; the door was open and I heard her at once."
"Did you hear or see anything else, previous to this?"
"Very early in the evening I saw Drevenoff going to his room on the third floor; I sat facing the doorway and had a view of the stairs."
"He did not come down again?"
"Not until Nanon called him."
"You are quite sure of that?"
"Quite. I should have seen him had he come down."
There was a pause of some length; the secret agent looked from one to the other of the two women, and finally he said to Nanon:
"You say that you are not sure that the second voice you heard in the library was Mr. Warwick's?"
Again came the quick, deep drawn breath from the girl; and again the gray eyes of the old woman sought her face. At the same time she replied: