“It may be so,” she said. “If she is so friendly with this banker whose past is quite obscure, it may be her hand which takes the stuff and passes it on to Zuccari, who in turn sells it to Hauser.”

With that theory I agreed.

On the following day I took train into Naples, and that afternoon I called upon the Marchesa.

Fortunately I found her alone, and when I was shown into her salon I thought she looked rather wan and pale, but she greeted me affably and expressed delight that I should call before returning to England.

As we chatted she let drop, as I expected she would, the fact that she had been staying at the Castello di Antigniano.

“You’ve seen in the papers, I suppose, all about the pearls of the Princess di Acquanero?” she went on. “A most mysterious affair!”

I looked the pretty woman straight in the face, and replied:

“Not so very mysterious, Marchesa.”

“Why not?” she asked, opening her big, black eyes widely.