It was the body of a man crushed almost past recognition by the weight of the fallen masonry. The labourers extricated it from the fragments of wood and metal and dragged it into the open.
"By his clothes," said one of the men, in answer to a peremptory query from the Man in Grey, "I guess he must be the butler, Francois Lavernay."
The secret agent made no comment. Not a line of his pale, colourless face betrayed the emotion he felt—the emotion of the sleuth-hound which knows that it is on the track of its quarry. He ordered the body to be decorously put on one side and took off his own loose mantle to throw over it. Then he bade the men resume their work. They picked up their tools again and tried to clear the rubbish all round the fallen stone.
"We must move that stone from its place," the man in the grey coat had said, and the labourers, impelled by that air of assurance and authority which emanated from the insignificant little figure, set to with a will. Having cleared the debris, they put their shoulders to the stone, helped by the secret agent whose strength appeared out of all proportion to his slender frame. By and by the stone became dislodged and, with another effort, rolled over on its flat side. After that it was easy to move it some three or four feet farther on.
"That will do!" commanded the Man in Grey.
Underneath the stone there now appeared a square flat slab of granite embedded into the soil with cement and concrete. One piece of this slab had seemingly been cut or chiselled away and then removed, displaying a cavity about a foot and a half square. In the centre of the slab was an iron ring to which a rope was attached, the other end being lost within the cavity.
The labourers were staring at their find open-mouthed; but the secret agent was already busy hauling up the rope. The end of it was formed into a loop not large enough to pass over a man's shoulders.
"Just as I thought," he muttered between his teeth.
Then he lay down on his stomach and with his head just over the small cavity he shouted a loud "Hallo!" From down below there came no answer save a dull, resounding echo. Again and again the Man in Grey shouted his loud "Hallo!" into the depths, but, eliciting no reply, at last he struggled to his feet.
"Now then, my men," he said, "I am going to leave you here to work away at this slab. It has got to be removed within an hour."