A sensation of profound relief that I was safe for a time at any rate was followed by some minutes of acute reaction in which I was incapable of consecutive thought. A mental blank from which I awoke pretty much as a man might wake from sleep-walking. I gazed about me unknowingly, and seeing the gate of a small public garden close at hand, I went in and sat down.
I soon began to get my wits in working order and bit by bit pieced things together. Curiously enough, almost the first thought was about the comparative trifle of the card case. I remember that I took it out and looked at it, wondering stupidly when I could have dropped it in Anna's room. Then I recalled that I had missed it in the morning when with von Gratzen. It couldn't have been in my pocket therefore when I went to Anna; and in a few seconds I understood.
The last time I had touched it was on the previous night when I had taken Rudolff's statement out of it to show von Erstein and he had tried to snatch the paper away and had only got the little case. I remembered that he had thrown it down close to him and had fiddled with it nervously afterwards.
It was clear that he had taken it away with him and had intentionally left it in Anna's room to shift his villainous deed on to me. It was worthy of him; and it would have succeeded but for that wonderful slice of luck—ineffably blessed luck, indeed—by which I had found the card case.
That helped me to piece the rest together. Panic-stricken by what I had told her about von Gratzen, Anna had no doubt threatened to expose everything; Erstein's whole scheme would be ruined the moment she opened her lips: and this had roused the brute in him until he had been driven to strangle her. The ring had slipped from his finger without his noticing the loss of it in his rage. Then he must have tossed my card case down under the table to connect me with the crime.
He had obviously left the door ajar for the same reason; had probably rushed to the first public telephone box and called me up in a voice which was enough like a woman's to mislead me; and intended to send some one to catch me red-hot on the scene of the crime.
Two points were not clear. Why no one had caught me? There had been ample time, supposing that he was hiding in wait for my arrival. And why had the murder been committed in Anna's room, seeing that she had gone from me to find him?
One of two suggestions seemed to answer the last question. Either she had not found him at first and had left a sufficiently urgent message to make him hurry to her, or that after a first interview he had induced her to go home and had followed at once. The plan to kill her must have been in his mind then, and obviously he couldn't do it in his own rooms.
The first question—why I had not been caught—wasn't so readily solved; but the ring might well account for it, if he had only discovered the loss of it in the interval of waiting for me. With that damning bit of evidence against himself, the bottom had dropped out of his scheme against me, and he would not dare to try and have me caught in the act.
And now I had fortunately shut the door against him. He couldn't go back for the ring even if he had the pluck, which I doubted.