"Are you trying to prove that the lead was already in the coffin when it was taken to the drawing-room?" I asked.
"No. I am only trying to show that it is doubtful whether the coffin was opened in the drawing-room."
"The change could not have been made in the bedroom, or the lead would have slipped during the journey downstairs," I said.
"I agree, and we are therefore forced to the assumption that the body was actually carried to the drawing-room, yet we are doubtful whether the coffin was opened there."
"I have no doubt," I returned.
"That is a mistake on your part, Wigan. Doubts are often the forerunners of convictions. My doubt led me to a curious discovery. When I went to the undertaker's I saw the men who actually made the coffin. It was a very plain coffin, less expensive than might have been expected for a man in Sir Grenville's position. Now one of the men, in answer to a careful question or two, mentioned a curious fact. In the floor of the coffin, close to the foot of it, there was a wart in the wood. This morning you saw me slit the lining and remove some of the padding. There was no wart in the floor of the coffin, Wigan."
"You mean the coffins were changed?" said Zena.
"I do. One with the body in it was removed, and another with lead in it was placed on the trestles in its stead. The plainer the coffin the easier it would be to duplicate it by description. The makers of the second coffin would not have the original before them to copy, you must remember."
"But only Lady Rusholm and her son could possess the necessary knowledge to give such a duplicate order," I said.
"You forget Mr. Thompson. He was an intimate friend, and staying in the house at the time."