"I was passing the house slowly when he came down the steps muttering fiercely to himself in Italian," Norah said. "He took no notice of me, for he seemed extremely angry and excited. Indeed, as he left, he glanced back at the house, his hands clenched, and he seemed to invoke a curse upon it." "By Jove!" I gasped. "That's interesting! The precious trio have perhaps quarrelled!" "Perhaps," said Hambledon. "And as a lawyer I venture to predict that if they really have we shall, ere long, obtain some very interesting disclosures." Norah stayed and had some supper, for we were all desperately hungry, and later on Harry saw her back to Richmond. Three days later, in consequence of a message sent to me from the Hotel Cecil, I went home early from the office to Rivermead Mansions, and had only been in five minutes when the door-bell rang. On opening it I found my expected visitor, Señor Rivero. "Ah! my dear friend!" cried the good-humoured police official, as he wrung my hand warmly. "So I have found you at last! The taxi-man made a mistake in the address and took me further down the road. Well, so you have been doing good business for us--eh? You have found Mateo Sanz!" "Yes. I recognized him," I said. "I have just been with Superintendent Risden, of Scotland Yard, and we have seen our friend whom we have wanted for so long. He is quite unsuspicious. But I am told that two days ago he visited the house of Mr. De Gex." "Yes, he is his friend, just as Despujol was," I remarked. "But I cannot understand that!" Rivero declared. "It seems incredible that a person of such high standing as Mr. De Gex should number bandits among his friends!" "I revealed to you the truth concerning De Gex when we were in Nîmes," I said. "Even then you were half inclined to disbelieve it. Now you know the truth. The two business partners of Oswald De Gex, the Conde de Chamartin, of Madrid, and the Baron van Veltrup, of Amsterdam, have both died suddenly--and at the instigation of their unsuspected friend! It has been proved that Sanz introduced the tiny scrap of infected razor-blade into the Baron's glove." "At De Gex's instigation?--impossible!" "De Gex was the only person to profit by the Baron's death," I pointed out. "He owed a large sum to the Baron over a financial deal, and by the latter's death, and the destruction of certain papers, he now escapes payment." "But you surely do not allege that Mr. De Gex resorts to the use of this little known and unsuspected poison in order to secure his own ends!" cried the famous detective, as he sat opposite me in an easy-chair.