"In God's name, what does it all mean?" I asked.

"It means murder," said he, stooping over the dead man. "Ah, I expected it. Look here!" He pointed to what looked like a long, dark thorn stuck in the skin just above the ear.

"It looks like a thorn," said I.

"It is a thorn. You may pick it out. But be careful, for it is poisoned."

I took it up between my finger and thumb. It came away from the skin so readily that hardly any mark was left behind. One tiny speck of blood showed where the puncture had been.

"This is all an insoluble mystery to me," said I. "It grows darker instead of clearer."

"On the contrary," he answered, "it clears every instant. I only require a few missing links to have an entirely connected case."

We had almost forgotten our companion's presence since we entered the chamber. He was still standing in the doorway, the very picture of terror, wringing his hands and moaning to himself. Suddenly, however, he broke out into a sharp, querulous cry.

"The treasure is gone!" he said. "They have robbed him of the treasure! There is the hole through which we lowered it. I helped him to do it! I was the last person who saw him! I left him here last night, and I heard him lock the door as I came downstairs."

"What time was that?"