“A piece of angular slate, well shaped for holdin’, provided with an almost sharp edge. Queer, isn’t it? Here’s a chap—I mean the guilty party—helped himself to what he wanted out of the armoury the night before; now, when he’s in a killin’ mood, he fetches along a stone. Plenty of rock like it in the Vale, of course. Seems likely, though, that it was picked up from that gimcrack rockery old Finlay wants to get rid of—just opposite the tower where Cosgrove was found.”
“You’re sure it’s the instrument?” I asked.
Salt looked at Aire, who said, “The Superintendent called in Doctor Niblett and me for our opinions on that point. The Coroner and I agree that in the hands of a vigorous person, who must have approached Cosgrove secretly from behind, the stone might well have done the damage.”
“But where was it lying?” I asked, with incredulity sounding in my tone. “How could we have missed it?”
“It wasn’t lyin’ anywhere,” answered Salt. “That’s a feature about it. It was embedded, sir, almost buried among the flowers outside the central windows of the Hall. If the rain hadn’t played hob with the beds, and the man Finlay with Mr. Blenkinson hadn’t been assessin’ the damage, it might have remained there unnoticed for a tidy while.”
“By Jove, though, that’s a far-fetched hiding-place.”
Salt raised his brows. “Is it? I think it was a clever one, sir. One second he strikes the blow, the next he hurls the weapon straight down into the loam. Inside half a minute he may be anywhere, and nothin’ to connect him with the crime. Just a little more energy, and the earth would have fallen in about the edges and covered the stone completely. But as it was it must have taken strength, gigantic strength.”
“It must have taken superhuman strength, Mr. Salt. Why, there had been rain, but it blew a bit easterly then, and those beds couldn’t have got much of it. It was nothing like last night’s inundation. The ground must have been hard.”
“On the contrary, the ground was exceedingly soft. Remember what it said in Mr. Blenkinson’s document, sir. Finlay had been waterin’ those very beds, and waterin’ ’em plenty after four o’clock.”
“Were there any marks on this stone?” asked Maryvale. “Any signs such as I understand often guide the police in their search?”