Gervais Aventin pulled himself together.
"I had no idea that the official police undertook espionage of that sort," he said rather drily. "But it is true, sir, that I went to Limoges—my last post before I was appointed to Vierzon—to take a final farewell to a lady. But since you are so accurately informed about all this, since you even know what train I went by, a train I deliberately chose because in little places like Vierzon so much notice is taken of people who travel by the express, you must also know——"
Juve checked him with a wave of the hand.
"A truce to jesting," he said; "excuse me, sir, I was only amusing myself by observing once more how quickly decent people, who have a little peccadillo on their conscience, are disturbed when they think they have been found out. Your love affairs do not matter to me, sir; I don't want to know if you have a lady friend, or not. The information I want from you is of a very different nature. Tell me simply this: in what circumstances did you make that journey? What carriage did you get into? Who travelled with you in that carriage? I am asking you because, sir, I have every reason to believe that you travelled that night with a murderer who committed a crime of particular atrocity, and I think you may be able to give me some interesting information."
The young man, who had been looking grave, smiled once more.
"I would rather have that than an enquiry into my defunct love affairs. Well, sir, I got into the train at Vierzon, into a first-class carriage——"
"One of the old-fashioned corridor carriages; that is to say, not a corridor communicating with the other carriages, but a single carriage with four compartments, two in the middle opening on to the corridor, and two at the ends communicating with the corridor by a small door."
"I know," said Juve; "the lavatory is in the centre, and the end compartments are like the ordinary noncorridor compartments, except that they have only seven seats, and also have the little door communicating with the narrow passage down one side of the carriage."
"That's it. I got into the smoking compartment at the end."