Evidently he had heard the whole conversation.

"I never for a moment imagined that he knew Madame Duclos.
Any knowledge we gain of her will have to come from Mrs.Taylor." "He's a strong man.

We shall find it difficult to hold our own against him if we are brought to an actual struggle." "Why did he run the forefinger of his right hand so continuously into his right-hand vest pocket ?" was Mr.Gryce's sole comment.
By which it looks as if he had seen as well as heard.
"I didn't notice it.

Is the District Attorney prepared to make the next move?
Mine has failed." "Not yet.

The game is too hazardous.