He considered the possibility of Bulmer having gone off of his own accord, for some reason; but after fully weighing it he finally dismissed it.  It was inconsistent with the unmistakable voice heard at daybreak, and with many other practical obstacles.  There was only one gateway in the ancient and lofty wall round the small park; the lodge keeper kept it locked till late in the morning, and the lodge keeper had seen no one pass.  Fisher was fairly sure that he had before him a mathematical problem in an inclosed space.  His instinct had been from the first so attuned to the tragedy that it would have been almost a relief to him to find the corpse.  He would have been grieved, but not horrified, to come on the nobleman’s body dangling from one of his own trees as from a gibbet, or floating in his own pool like a pallid weed.  What horrified him was to find nothing.

He soon become conscious that he was not alone even in his most individual and isolated experiments.  He often found a figure following him like his shadow, in silent and almost secret clearings in the plantation or outlying nooks and corners of the old wall.  The dark-mustached mouth was as mute as the deep eyes were mobile, darting incessantly hither and thither, but it was clear that Brain of the Indian police had taken up the trail like an old hunter after a tiger.  Seeing that he was the only personal friend of the vanished man, this seemed natural enough, and Fisher resolved to deal frankly with him.

“This silence is rather a social strain,” he said.  “May I break the ice by talking about the weather?—­which, by the way, has already broken the ice.  I know that breaking the ice might be a rather melancholy metaphor in this case.”

“I don’t think so,” replied Brain, shortly.  “I don’t fancy the ice had much to do with it.  I don’t see how it could.”

“What would you propose doing?” asked Fisher.

“Well, we’ve sent for the authorities, of course, but I hope to find something out before they come,” replied the Anglo-Indian.  “I can’t say I have much hope from police methods in this country.  Too much red tape, habeas corpus and that sort of thing.  What we want is to see that nobody bolts; the nearest we could get to it would be to collect the company and count them, so to speak.  Nobody’s left lately, except that lawyer who was poking about for antiquities.”

“Oh, he’s out of it; he left last night,” answered the other.  “Eight hours after Bulmer’s chauffeur saw his lawyer off by the train I heard Bulmer’s own voice as plain as I hear yours now.”

“I suppose you don’t believe in spirits?” said the man from India.  After a pause he added:  “There’s somebody else I should like to find, before we go after a fellow with an alibi in the Inner Temple.  What’s become of that fellow in green—­the architect dressed up as a forester?  I haven’t seem him about.”

Mr. Brain managed to secure his assembly of all the distracted company before the arrival of the police.  But when he first began to comment once more on the young architect’s delay in putting in an appearance, he found himself in the presence of a minor mystery, and a psychological development of an entirely unexpected kind.