“And Miss Morriston?” Henshaw put the question in a tone which had in it, Gifford thought, a touch of scepticism.

“Oh, my sister must have been in here too,” Morriston replied.  “Or how could her dress have been stained?  Unless, indeed, she brushed against Miss Tredworth’s or someone else’s.  That’s clear.”

There seemed no alacrity in Henshaw to accept the conclusion and he did not respond.

“I am glad this part of the mystery is so satisfactorily settled,” the chief constable remarked.  “Now we have the issue narrowed.  Well, Sprules?”

The detective had appeared at the door.

“I have examined the ironwork of the window, sir,” he said, “and have found under the magnifying-glass traces of the fraying of a rope as though caused by friction against the iron staple.”

“Sufficient signs to bear out the young woman’s statement?”

“Quite, sir.  There is upon close examination distinct evidence of a rope having been worked against the hinge of the window.”

“Very good, Sprules.  We may consider that point settled,” Major Freeman said.

Having finally satisfied themselves as to the cause of the stains on the floor and sofa, the chief constable and his subordinate proposed to go to the lake and see whether the men who were dragging it had had any success.  Morriston and Henshaw with Kelson and Gifford accompanied them.  As they came in sight of the boat the detective exclaimed, “They have found it!” and the men were seen hauling up a rope out of the water.

“Sooner than I expected,” Major Freeman observed as they hurried towards the nearest point to the boat.

The rope when landed proved to be of considerable length, sufficient when doubled, they calculated, to reach from the topmost window to within five or six feet of the ground.

“The escaping person,” Henshaw said, “must have slid down the doubled rope which had been passed through the staple of the window, and then when the ground was reached have pulled it away, coiled it up, carried it to the lake, and thrown it in.  Obviously that was the procedure and it accounts completely for the locked door.”

The chief constable and the detective agreed.

“A man would want some nerve to come down from that height,” the latter remarked.

“Any man, or woman either for that matter,” Henshaw returned dogmatically, “would not hesitate to take the risk as an alternative to being trapped up there with his victim.”

“You are not suggesting it might have been a woman who was seen sliding down the rope?” Gifford asked pointedly.

Henshaw shrugged.  “I suggest nothing as to the person’s identity,” he replied in a sharply guarded tone.  “That is now what remains to be discovered.”

CHAPTER XVIII

THE LOST BROOCH

The police authorities with Henshaw and Morriston went off with the rope to experiment in the room of the tragedy.