The Superintendent was silent. After a moment Giles added, with a faint smile: “Moreover, I hardly think he would have overlooked the cartridge-case.”
“You think I'm prejudiced against young Vereker,” said Hannasyde. “But I can honestly say that I hope very much you may be right. But it's no use blinking facts: Roger Vereker's death - assuming it to have been murder - narrows the field down considerably. I don't think there's much doubt that the man who killed Arnold also killed Roger. You yourself said that although there might have been several motives for the first murder there can only have been one for the second. That seems to dispose of Mesurier for one, and of Arnold's chauffeur - never a probable suspect, I admit - for another. Neither stood to gain anything through Roger's death. There is just one person who stands to gain a fortune; you know it as well as I do, so we may as well be frank about it. What is more, Mr Carrington, you have never been sure that Kenneth Vereker didn't commit that first murder. You believed him to be capable of it, I've known that from the start. What sticks in your gullet is this second murder. But if you think it over you must see that it follows perfectly logically, almost inevitably, on the first. Admitted, it wasn't foreseen. It takes a pretty hardened criminal to plan to kill two people. One murder only was planned, but when Roger Vereker turned up that murder was useless unless he also could be got rid of. You know the French saying that it's only the first step that counts: well, you can apply it here. If a man can murder one half-brother for his money, and get away with it, he won't find it so hard to murder a second half-brother. And I don't in the least mind admitting that Arnold's murderer looked like getting away with it completely - which Kenneth Vereker was well aware of.”
“It would have to be an abnormal mind!” Giles said harshly.
“Yes, certainly.”
“Rubbish! That boy's not abnormal at all. Nor, had he planned to kill Roger, would he have been fool enough to show his animosity so plainly.”
“Wouldn't he?” Hannasyde's voice was very dry. “I think that is just what Kenneth Vereker would do. But don't run away with the idea that I've ruled out every other possible suspect. I haven't - but I should be a fool if I didn't go into his movements last night very carefully.”
They had come to a crossing, and the traffic lights were against them. Not until the car had moved forward again did Giles Carrington answer. Then he said, with a smile: “Yes, you'd be a fool - but I told you I was going to take a hand, didn't I?”
“Well, if anything has occurred to you, let me have it,” said Hannasyde placably.
“Two possibilities have occurred to me, but both are so wildly improbable that I think I won't bother you with them,” replied Giles. “One is obvious enough for you to have thought of for yourself -”
Hannasyde gave a chuckle. “Thank you!”