As he stooped at the place where the chair had been, a bright object sticking to the curtain caught his eye. He looked more closely. A small, slightly bent, gold safety-pin, bearing a tiny row of diamonds, was caught in the braid at the top of the hem. The point had not penetrated, and the pin fell to the floor when Burnley touched the plush. He picked it up. ‘That’s rather a fine thing even for a natty boy like Felix,’ he said as he showed it to Kelvin. And then he stood quite still as it flashed across his mind that here, perhaps, was another link in the chain that was being forged about Felix--a link possibly even more important than any of the foregoing. What if it did not belong to Felix at all? It looked too dainty and delicate for a man’s use. What if it was a lady’s? And, most important question of all, what if that lady was Mme. Boirac? If this proved true, his case was complete. Dropping into the arm-chair he had occupied on the occasion of his midnight interview with Felix, he considered the possibilities opened up by his new discovery, endeavouring to evolve some theory of how a pin or brooch belonging to the deceased lady could have been dropped where he found this one. As he did so, a picture of what might have happened gradually grew in his mind. First, he thought it likely that a lady in evening dress would wear such a pin, and it might easily be at her neck or shoulder. And if she had sat in that chair with her back to the curtain, and any one had caught her by the throat and forced her head backwards, what could be more likely than that the pin should be pulled out in the struggle? And if it were pulled out it almost certainly would drop where or whereabouts he found it. The Inspector recognised again that this was all surmise, but it was strengthened by the fact that the pin was undoubtedly bent as if it had been pulled out of something without being unhooked. The more he thought over it the more likely his idea seemed. At all events it would be easy to test it. Two points suggested themselves to his mind which would settle it conclusively. First, if the pin were Madame’s, the maid Suzanne would recognise it. The arrangement of the diamonds made it quite distinctive. The girl would also know if Madame wore it on the night of the dinner-party. Secondly, if it were pulled out of Madame’s dress, the latter would probably be torn or at least marked. Both these points could easily be ascertained, and he decided he would write to Paris about them that night.