‘And now, Mr. Felix, can you not think of any others who may have known about the cask?’
‘There was no one,’ replied the other with decision.
‘I’m afraid we can’t assume that. We certainly can’t be sure.’
‘Who could there be?’
‘Well, your French friend. How do you know he didn’t write to others beside you?’
Felix sat up as if he had been shot.
‘By Jove!’ he cried, ‘it never entered my head. But it’s most unlikely—most unlikely.’
‘The whole thing’s most unlikely as far as that goes. Perhaps you are not aware that some one else was watching the house last evening?’
‘Good God, Inspector! What do you mean?’
‘Some one came to the lane shortly after your arrival with the cask. He waited and heard your conversation with your friend Martin. When you and your friend left, he followed you.’