"Mystery!" he added as if in answer to Polly's own thoughts. "The murder of that man was never a mystery to me. I cannot understand how the police could have been so blind when every one of the witnesses, both for the prosecution and defence, practically pointed all the time to the one guilty person. What do you think of it all yourself?"
"I think the whole case so bewildering," she replied, "that I do not see one single clear point in it."
"You don't?" he said excitedly, while the bony fingers fidgeted again with that inevitable bit of string. "You don't see that there is one point clear which to me was the key of the whole thing?
"Lavender was murdered, wasn't he? Lord Arthur did not kill him. He had, at least, in Colonel McIntosh an unimpeachable witness to prove that he could not have committed that murder—and yet," he added with slow, excited emphasis, marking each sentence with a knot, "and yet he deliberately tries to throw the guilt upon a man who obviously was also innocent. Now why?"
"He may have thought him guilty."
"Or wished to shield or cover the retreat of one he knew to be guilty."
"I don't understand."
"Think of someone," he said excitedly, "someone whose desire would be as great as that of Lord Arthur to silence a scandal round that gentleman's name. Someone who, unknown perhaps to Lord Arthur, had overheard the same conversation which George Higgins related to the police and the magistrate, someone who, whilst Chipps was taking Lavender's card in to his master, had a few minutes' time wherein to make an assignation with Lavender, promising him money, no doubt, in exchange for the compromising bills."
"Surely you don't mean—" gasped Polly.
"Point number one," he interrupted quietly, "utterly missed by the police. George Higgins in his deposition stated that at the most animated stage of Lavender's conversation with Lord Arthur, and when the bookmaker's tone of voice became loud and threatening, a voice from the top of the steps interrupted that conversation, saying: 'Your tea is getting cold.'"