"He added this last question with an involuntary eagerness that scarcely accorded with the indifferent tone with which he had begun. I answered guardedly. I said of course nobody could say what the unhappy man's sins might have been, but that whatever they were they could never justify the fearful sin of murder. 'And,' I added, 'if you know anything of the matter, Mason, or have the smallest suspicion as to who is the guilty person, I'm sure you won't hesitate in your duty.'
"'My duty?' he said. 'Oh yes, of course; my duty. You mean, of course, that any law-abiding citizen who knows of evidence should bring it out. Just so. Of course I haven't any evidence—that paper gave me the first news of the thing.'
"'I think,' I rejoined, 'that anybody who was possessed of even less than evidence—of any suspicion which might lead to evidence—should go at once and place the authorities in possession of all he knows or suspects.'
"'Yes,' he said—very calmly now, though it seemed at cost of a great effort—'so he should; so he should, no doubt, in any ordinary case. But sometimes there are difficulties, you know—great difficulties.' He stopped and looked at me furtively and uneasily. 'A man might fear for his own safety—he might even know that to say what he knew
