"But who is this doctor? Who is this malevolent genius, this infernal being who appears and disappears, who slays in the dark and whom nobody suspects?"
"Can't you guess?"
"No."
"And do you want to know?"
"Do I want to know?... Why, speak, man, speak!... You know where he is hiding?"
"Yes."
"In this house?"
"Yes."
"And it is he whom the police are after?"
"Yes."