'I see no reason to suppose that the man was drowned. If able to swim he could easily have reached the river bank. If unable to swim, why should he attempt it encumbered by the box?'
'You believe he escaped, then?'
'I think so.'
'It will be lucky for you should that prove to be the case.'
'Certainly.'
'How did you come to be in the yacht at all?' 'I shall give you a full account of the affair, concealing nothing. I am a private detective, with an office in London. I was certain that some attempt would be made, probably by the most expert criminals at large, to rob the possessor of this necklace. I came over to Paris, anticipating trouble, determined to keep an eye upon the jewel case if this proved possible. If the jewels were stolen the crime was bound to be one of the most celebrated in legal annals. I was present during the sale, and saw the buyer of the necklace. I followed the official who went to the bank, and thus learned that the money was behind the cheque. I then stopped outside and waited for the buyer to appear. He held the case in his hand.'
'In his pocket, you mean?' I interrupted.
'He had it in his hand when I saw him. Then the man who afterwards jumped overboard approached him, took the case without a word, held up his hand for a cab, and when an open vehicle approached the curb he stepped in, saying, "The Madeleine." I hailed a closed cab, instructed the cabman to follow the first, disguising myself with whiskers as near like those the man in front wore as I had in my collection.'
'Why did you do that?'
'As a detective you should know why I did it. I wished as nearly as possible to resemble the man in front, so that if necessity arose I could pretend that I was the person commissioned to carry the jewel case. As a matter of fact, the crisis arose when we came to the end of our cab journey. The captain did not know which was his true passenger, and so let us both remain aboard the launch. And now you have the whole story.'