Hanaud leaned across and tapped his fingers on the table to emphasise his answer.

"All through this crime there are two things visible—brains and daring; clever brains and extraordinary daring. Would he have dared? He dared to be at the corner close to the Villa Rose at daylight. Why else should he have returned except to put back the car? Consider! The petrol is taken from tins which Servettaz might never have touched for a fortnight, and by that time he might, as he said, have forgotten whether he had not used them himself. I had this possibility in my mind when I put the questions to Servettaz about the petrol which the Commissaire thought so stupid. The utmost care is taken that there shall be no mould left on the floor of the carriage. The scrap of chiffon was torn off, no doubt, when the women finally left the car, and therefore not noticed, or that, too, would have been removed. That the exterior of the car was dirty betrayed nothing, for Servettaz had left it uncleaned."

Hanaud leaned back and, step by step, related the journey of the car.

"The man leaves the gate open; he drives into Geneva the two women, who are careful that their shoes shall leave no marks upon the floor. At Geneva they get out. The man returns. If he can only leave the car in the garage he covers all traces of the course he and his friends have taken. No one would suspect that the car had ever left the garage. At the corner of the road, just as he is turning down to the villa, he sees a sergent-de-ville at the gate. He knows that the murder is discovered. He puts on full speed and goes straight out of the town. What is he to do? He is driving a car for which the police in an hour or two, if not now already, will be surely watching. He is driving it in broad daylight. He must get rid of it, and at once, before people are about to see it, and to see him in it. Imagine his feelings! It is almost enough to make one pity him. Here he is in a car which convicts him as a murderer, and he has nowhere to leave it. He drives through Aix. Then on the outskirts of the town he finds an empty villa. He drives in at the gate, forces the door of the coach-house, and leaves his car there. Now, observe! It is no longer any use for him to pretend that he and his friends did not disappear in that car. The murder is already discovered, and with the murder the disappearance of the car. So he no longer troubles his head about it. He does not remove the traces of mould from the place where his feet rested, which otherwise, no doubt, he would have done. It no longer matters. He has to run to earth now before he is seen. That is all his business. And so the state of the car is explained. It was a bold step to bring that car back—yes, a bold and desperate step. But a clever one. For, if it had succeeded, we should have known nothing of their movements—oh, but nothing—nothing. Ah! I tell you this is no ordinary blundering affair. They are clever people who devised this crime—clever, and of an audacity which is surprising."

Then Hanaud lit another cigarette.

Mr. Ricardo, on the other hand, could hardly continue to smoke for excitement.

"I cannot understand your calmness," he exclaimed.

"No?" said Hanaud. "Yet it is so obvious. You are the amateur, I am the professional—that is all."

He looked at his watch and rose to his feet.

"I must go" he said and as he turned towards the door a cry sprang from Mr. Ricardo's lips "It is true. I am the amateur. Yet I have knowledge, Monsieur Hanaud which the professional would do well to obtain."