It was close to eleven o'clock when Fred arrived. I took him to the kitchen, because Wolfe was still consulting the encyclopedia, though he must have finished with Thales long ago. When Saul came, I sent him to join Fred in the kitchen and told Wolfe to let us know when he was ready for company, and he glared at me because he was in the middle of an interesting article. The way I know it was interesting is that there isn't a single page in the whole twenty-four volumes that he wouldn't think was interesting. I went to the kitchen and brought them, and Saul took the red leather chair and Fred one of the yellow ones.
That was the shortest session with the help on record. "I apologize," Wolfe said, "for getting you out so late on a winter night, but I need you. There has been a development. The man who maintained that apartment for Miss Kerr – call him X – is in the front room. He came to tell me something that he should have told me two days ago. Last September a man telephoned him and demanded money. The man knew of his visits to that apartment and threatened to make them impossible unless the money was paid, a thousand dollars at once and a thousand dollars a month, in cash, to be mailed to him at general delivery – an assumed name, of course. The money has been paid, a total of five thousand dollars. X is convinced, for reasons he considers valid, that the blackmailer is Orrie Cather. Sunday evening I asked your opinion as to whether Orrie had killed Miss Kerr. I now ask your opinion as to whether he is a blackmailer. Did he blackmail X? Fred?"
Fred was frowning, concentrating. "Just like you said?" he asked. "Just straight open-and-shut blackmail?"
"Yes."
Fred shook his head. "No, sir. Impossible."
"Saul?"
"To be sure I have it right," Saul said, "this was at the time when Orrie was seeing her himself?"
"Yes."
"Then no. As Fred said, impossible. That would take a real snake."
"Satisfactory," Wolfe said. "Archie and I had made our conclusion, and I know, barely short of certainty, who the blackmailer is, but I wanted your opinions. I didn't get you here just for that; there will be instructions for tomorrow. Archie, may they wait in your room?"