"Yes. I have it here. Will you take it?"
"Perhaps I'd better," he replied after a pause, and then opened the drawer containing the portfolio, tossed it in carelessly, and let me finish the rest of the story without interruption, when he once more lapsed into close thought.
Von Welten came in before he spoke and handed him a note. "Not a second later than seven o'clock, mind, von Welten. Not a second, mind," he said when he had read the letter. "That'll do;" and we were alone again.
"Now I'll tell you something in my turn," he said. "You have rendered us a very great service; a much greater service than you can imagine. You have only made one mistake, for you ought to have hurried to me as fast as possible from that woman's rooms; but you're evidently lucky, for no harm has been done."
"I don't quite understand, sir," I stammered in surprise.
"I'm going to explain it to you. In the first place let me tell you I believe absolutely that you have told me the truth—about this murder, I mean—perhaps not in everything else."
"There is only one thing, and if you wish——"
"Don't interrupt me, boy. I don't like it," he exclaimed testily. "It puts me out. Now about this affair. We know all about this woman, Anna Hilden. That isn't her name at all; but that doesn't matter now. She is, or was, one of von Erstein's mistresses; not the only one, by the way. The real Anna Hilden was another—years ago, of course—and that is how he knew all about that sale of the secret information to France."
I had not said anything about that and he noticed my start.
"You needn't be astonished. I tell you we know many things here. It is our business to know them. The man who betrayed us in that affair was von Erstein himself, and you, if you are really Lassen, were merely the go-between and scapegoat. But he was too cunning for us to be able to prove a thing against him. There are many things we think we know about him and can't prove, and others we don't wish to prove," he said, with a very meaning side glance.