“The main fact is that he had the pearl, and at that moment, when it was on his person, he was pursued by the police.  He made for the factory in which he worked, and he knew that he had only a few minutes in which to conceal this enormously valuable prize, which would otherwise be found on him when he was searched.  Six plaster casts of Napoleon were drying in the passage.  One of them was still soft.  In an instant Beppo, a skilful workman, made a small hole in the wet plaster, dropped in the pearl, and with a few touches covered over the aperture once more.  It was an admirable hiding-place.  No one could possibly find it.  But Beppo was condemned to a year’s imprisonment, and in the meanwhile his six busts were scattered over London.  He could not tell which contained his treasure.  Only by breaking them could he see.  Even shaking would tell him nothing, for as the plaster was wet it was probable that the pearl would adhere to it—­as, in fact, it has done.  Beppo did not despair, and he conducted his search with considerable ingenuity and perseverance.  Through a cousin who works with Gelder, he found out the retail firms who had bought the busts.  He managed to find employment with Morse Hudson, and in that way tracked down three of them.  The pearl was not there.  Then, with the help of some Italian employee, he succeeded in finding out where the other three busts had gone.  The first was at Harker’s.  There he was dogged by his confederate, who held Beppo responsible for the loss of the pearl, and he stabbed him in the scuffle which followed.”

“If he was his confederate, why should he carry his photograph?” I asked.

“As a means of tracing him, if he wished to inquire about him from any third person.  That was the obvious reason.  Well, after the murder I calculated that Beppo would probably hurry rather than delay his movements.  He would fear that the police would read his secret, and so he hastened on before they should get ahead of him.  Of course, I could not say that he had not found the pearl in Harker’s bust.  I had not even concluded for certain that it was the pearl, but it was evident to me that he was looking for something, since he carried the bust past the other houses in order to break it in the garden which had a lamp overlooking it.  Since Harker’s bust was one in three, the chances were exactly as I told you—­two to one against the pearl being inside it.  There remained two busts, and it was obvious that he would go for the London one first.  I warned the inmates of the house, so as to avoid a second tragedy, and we went down, with the happiest results.  By that time, of course, I knew for certain that it was the Borgia pearl that we were after.  The name of the murdered man linked the one event with the other.  There only remained a single bust—­the Reading one—­and the pearl must be there.  I bought it in your presence from the owner—­and there it lies.”

We sat in silence for a moment.