“Humph!” muttered Puttler, and continued his search – a search which yielded no further evidence.

Retracing their steps, they passed the study door, and Puttler, who was walking a little ahead, stumbled over something, and put his light to the ground.

“You keep rather a lot of ladders about here, Mr Alford,” he said, in a low voice. “A library ladder outside? What’s the great idea?”

The ladder was lying parallel with the gravel drive, and Puttler examined it rung by rung.

“That wasn’t here last night, I’ll take my oath,” he said.

“No,” said Dick, puzzled; “it usually hangs on two pegs near the garage.”

He lifted it up. It was a long, light, triangular ladder tapering to a point at the top, and used by the staff for outside window cleaning.

“You had better have it chained up,” was all Puttler said after he had finished his inspection. “The man who brought this here was the man who cut off your light supply, and, incidentally–”

Far away in the grounds came the faint sound of a man’s voice, challenging in military fashion.

“Halt! Who goes there?”

“That’s Renwick, a local man,” said Puttler immediately.

They ran towards the sound of the voice, and presently saw the flicker of his lantern; and it was a badly scared man who challenged them a few minutes later. He had seen nothing, he said, but he had heard voices.

“One of them was laughing. I thought at first it was you, sergeant, but when I heard it again it was so wild that I got a little nervous.”

“Did anybody answer your challenge?”

“No, but the voices stopped. I couldn’t hear the woman’s voice–”

“The woman’s voice?” said Dick quickly. “Was it a woman? Surely you’re mistaken?”

“I could swear to it,” said the watcher. “It was the woman’s voice I heard first, and the man who laughed. I think the voices must have stopped as soon as I put my lamp on.”

“In what direction?”

The policeman pointed across Long Meadow, the shallow, valley-like depression which ran parallel with the rising ground on which the abbey stood. To the left there were a number of cottages, occupied in the main by people working on the estate, two gamekeepers, a carter and a groom. It was from one of these cottages that the Black Abbot had been seen and reported by a terrified gamekeeper.

“They sounded as if they were walking away from you over the Mound to the river – or to the ruins?” suggested Puttler.

“Well,” confessed the man, “they might have been going that way: I can’t be sure.”

“That certainly beats the band,” said the sergeant, as they were moving in the direction the man had indicated.

“He must have been mistaken,” said Dick with emphasis. “They were walking away from him–”

“They,” repeated Puttler significantly. “I don’t think he was wrong at all.”