Hanaud rose to his feet and handed the shoes back to the officer.

“Yes,” he said, “so it seems.  The shoemaker can help us here.  I see the shoes were made in Aix.”

Besnard looked at the name stamped in gold letters upon the lining of the shoes.

“I will have inquiries made,” he said.

Hanaud nodded, took a measure from his pocket and measured the ground between the window and the first footstep, and between the first footstep and the other two.

“How tall is Mlle. Celie?” he asked, and he addressed the question to Wethermill.  It struck Ricardo as one of the strangest details in all this strange affair that the detective should ask with confidence for information which might help to bring Celia Harland to the guillotine from the man who had staked his happiness upon her innocence.

“About five feet seven,” he answered.

Hanaud replaced his measure in his pocket.  He turned with a grave face to Wethermill.

“I warned you fairly, didn’t I?” he said.

Wethermill’s white face twitched.

“Yes,” he said.  “I am not afraid.”  But there was more of anxiety in his voice than there had been before.

Hanaud pointed solemnly to the ground.

“Read the story those footprints write in the mould there.  A young and active girl of about Mlle. Celie’s height, and wearing a new pair of Mlle. Celie’s shoes, springs from that room where the murder was committed, where the body of the murdered woman lies.  She is running.  She is wearing a long gown.  At the second step the hem of the gown catches beneath the point of her shoe.  She stumbles.  To save herself from falling she brings up the other foot sharply and stamps the heel down into the ground.  She recovers her balance.  She steps on to the drive.  It is true the gravel here is hard and takes no mark, but you will see that some of the mould which has clung to her shoes has dropped off.  She mounts into the motor-car with the man and the other woman and drives off—­some time between eleven and twelve.”

“Between eleven and twelve?  Is that sure?” asked Besnard.

“Certainly,” replied Hanaud.  “The gate is open at eleven, and Perrichet closes it.  It is open again at twelve.  Therefore the murderers had not gone before eleven.  No; the gate was open for them to go, but they had not gone.  Else why should the gate again be open at midnight?”

Besnard nodded in assent, and suddenly Perrichet started forward, with his eyes full of horror.

“Then, when I first closed the gate,” he cried, “and came into the garden and up to the house they were here—­in that room?  Oh, my God!” He stared at the window, with his mouth open.

“I am afraid, my friend, that is so,” said Hanaud gravely.

“But I knocked upon the wooden door, I tried the bolts; and they were within—­in the darkness within, holding their breath not three yards from me.”