Beyond a murmured acknowledgment, Inspector Tanner did not reply for some moments, as he thought over what he had just heard. There were obviously two theories about it. First, if the story were true it cleared Austin, not merely as an alibi, but it accounted for his suspicious manner. And the Inspector could see no reason why it should not be true. Such a plant on the part of the murderer, with the object of throwing suspicion on Austin, and therefore off himself, would be quite possible. It would be proved that Austin took a boat, and went down the river, and was away long enough for him to have reached the Luce Manor boathouse and committed the murder. And the ruined Abbey was just the place the inventor of such a plant would choose, a deserted spot where Austin would be unlikely to meet anyone who could confirm his story.
On the other hand, Austin might really know the truth, even if he was not himself the actual murderer. If so, the story was a clever invention on his part, well designed and thought out. But whichever of these theories were true, it was obvious to Tanner that he must test the whole thing as thoroughly as he possibly could.
‘If you will allow me to say it, sir,’ he observed, ‘you did a wise thing in telling me this story. Had you not done so, and had I found out about your using the boat, I should have taken a very different view of the affair. And now for your own sake, as well as mine, I feel sure you won’t object to my testing your statement. You say the path to this ruin was muddy. There has been no rain since Wednesday. Your footprints will therefore be clear. Come into Halford with me now, and lend me the shoes you wore that night, and I will go out to the place and see the marks with my own eyes.’
Austin slapped his thigh.
‘Capital, Inspector!’ he cried. ‘The more you test it the better I’ll be pleased. It will be no end of a weight off my mind. I don’t deny I have been horribly worried.’
His manner did not belie his statement. As a few minutes later he drove Tanner and the sergeant into Halford, he seemed to have thrown off his depression, and chatted easily and almost gaily.
They drew up at the door of his small villa. It was opened by a butler rather resembling Parkes, but younger and slighter.
‘Come in, Inspector, and I’ll give you what you want. Will you wait here a moment?’
Austin led the way into a cheerful room fitted up as a study and workroom. A large table in the corner was littered with papers and manuscripts, there was a fine microscope in the window, while everywhere were strewn books and periodicals. The Inspector moved about noting and memorising what he saw, till Austin returned.
‘There you are,’ the latter exclaimed, holding out a pair of tan shoes, ‘and here’s a bag to put them in.’