‘Possibly,’ replied Mr. Gordon a trifle dryly, ‘but you probably can form an opinion on that as well as I.’ Burnley smiled. ‘We Scotland Yard people like to know everything,’ he said. ‘And now, Mr. Gordon, I have to express my thanks for your courtesy and help.’ ‘That’s all right. Would it be indiscreet to ask the reason of these queries?’ ‘Not at all, sir, but I fear I am not at liberty to give you much information. The man with the pointed beard is suspected of having decoyed a French lady over to England and murdered her. But, you will understand, it is so far only a matter of suspicion.’ ‘Well, I should be interested to hear how it turns out.’ ‘I am afraid you will hear, sir. If this man is tried, I expect your evidence will be required.’ ‘Then for both our sakes I hope your case will not go on. Good-day, Mr. Burnley. Glad to have met you.’ There being nothing to keep him in Glasgow, the Inspector returned to the Central and took the midday London express. As it thundered southwards across the smiling country, he thought over the interview he had just had. He could not help marvelling again at the luck that had pursued his efforts ever since the inquiry began. Nearly every one he had interviewed had known at least something, if not always exactly what he wanted. He thought how many thousands of persons crossed the Channel each week whose journey it would be absolutely impossible to trace, and here, in the one instance that mattered, he had found a man who had been able to give him the very information he needed. Had Felix not gone in the bus, had Mr. Gordon not been so observant, had the circumstances not fallen out precisely as they did, he might never have ascertained the knowledge of Felix’s movements that day. And the same applied all through. Truly, if he did not get a complete case it would be his own fault. And yet the evidence was unsatisfactory. It was never conclusive. It had a kind of thus-far-and-no-farther quality which always pointed to a certain thing, but stopped short of certainty. Here there was a strong presumption that Mme. Boirac had crossed with Felix, but no proof. It might, however unlikely, have been some one else. Nearly all the evidence he had got was circumstantial, and he wanted certainty.