Sir Clinton seemed inclined to dispute this conclusion, but he restrained himself and merely nodded to Wendover to continue.
“I see your objection, I think,” the Squire went on. “You meant to say: ‘Why were both the Shandons murdered when it was only Neville’s death that was essential to Hackleton?’ But there’s quite a plausible explanation of that. You can’t hang a man twice. So if a man decides to commit a single murder, he might as well commit two. The punishment’s the same for a quantity. And if he can commit two with equal impunity—as in the Maze—mightn’t it occur to him that two murders would be a stiffer problem than one murder, in these particular circumstances? Isn’t it the double murder that’s giving all the difficulty? Of course it is. If either Shandon had been murdered solus, we’d know at once the line to look up. But at present we don’t. Now why shouldn’t the murderer have seen that very point and utilised it?”
Sir Clinton nodded.
“That’s ingenious, Squire. I’m not ironical.”
“I’d rather choose that solution than any of the other possible ones. If you reject it, you’ve got to assume that two independent murderers, both using the same out-of-the-way method, chose to operate simultaneously. The chances against that are miles too big. Or else you have to believe that two co-operating murderers were at work and that each of them thought he had the right victim in front of him. I can’t quite swallow the notion that this was a co-operative affair. The third solution is that the murderer mistook one brother for the other, killed Roger first, and then had to kill Neville to carry out his instructions. He might have had only a general description of Neville Shandon to go on and may have made a mistake in identity.”
“I doubt if Hackleton would have left any loophole of that sort,” Sir Clinton interrupted. “Neville’s portrait could easily have been bought and given to the murderer. But it’s not worth while arguing the point. The murderer knew the two Shandons perfectly well by sight. I’m sure of my ground there.”
“You mean the murderer was a local man?” demanded Wendover. “How did you find that out?”
“I’m not going to tell you at present, Squire. Sorry to play the mystery-man, and all that sort of stuff; but it has to be done.”
Wendover was plainly distrustful of this point.
“If it was a local affair, what was the black silk thread then? The thread we found in the Maze not a couple of hours ago.”