"No, no, sir; no, not against you!" It was a woman's voice, and Mrs. Barrymore, paler and more horror-struck than her husband, was standing at the door. Her bulky figure in a shawl and skirt might have been comic were it not for the intensity of feeling upon her face.
"We have to go, Eliza. This is the end of it. You can pack our things," said the butler.
"Oh, John, John, have I brought you to this? It is my doing, Sir Henry—all mine. He has done nothing except for my sake and because I asked him."
"Speak out, then! What does it mean?"
"My unhappy brother is starving on the moor. We cannot let him perish at our very gates. The light is a signal to him that food is ready for him, and his light out yonder is to show the spot to which to bring it."
"Then your brother is—"
"The escaped convict, sir—Selden, the criminal." (9.65-71)
So, the Barrymores are feeling guilty about something, but not about what Sir Henry and Watson expect. In fact, they've secretly been sheltering the escaped convict Selden, since he's Mrs. Barrymore's little brother. Up until now, all of the clues seem to indicate that the butler's the threat facing Sir Henry. But we're only in the ninth chapter of the novel out of fifteen. If Barrymore were really the killer, what would the remaining six chapters be about?