"One day I handed one of them to Karkowsky, and he threw it back at me.
"'That's not for me,' he said. And sure enough it wasn't. It was for another party a couple of blocks away--a party that was new to my route. This same mistake happened a couple of times--me being so used to the letters that I never looked at 'em twice--and every time old Karkowsky got his back up. One day I kidded him about losing his girl and said I guessed some other fellow had won her out, seeing that he was getting all the letters, and Karkowsky swore. He called me some hard names that day and threatened to report me. So I cut out the jokes."
"When the letters began arriving for the second person they ceased for Karkowsky?"
There was a moment's silence; then the secret agent asked:
"Can you recall this other person's name?"
"Oh, yes. It's Kendreg. He lives on the top floor of 424 Lowe Street."
After Ashton-Kirk had hung up he sat for a few moments, a peculiar expression on his face. Then he pressed one of the row of buttons. While awaiting a response, he penciled a few lines upon a tablet; when Fuller came in he tore off the sheet and handed it to him.
"Give this to Burgess," he requested. "Have him look this person up quietly. Tell him to work under cover as much as possible; and to especially note if he has any women visitors."
"Very well," said Fuller; and turning he left the room.
Ashton-Kirk was at breakfast next morning when Fuller entered.
"I beg pardon," said the assistant, "but I've just had a call from Burgess, and I thought you'd like to hear what he had to say."
"He went to 424 Lowe Street last night after I gave him your instructions. It's a large building, once used as a factory, but now rearranged as an apartment house. There was a gas-lighted sign over the door which said rooms might be had. Burgess took one on the fourth floor, and in a conversation with the caretaker mentioned that he had a friend, a Pole, who had lived there.
"'Do you know Kendreg?' says the caretaker. 'He's right across the hall from you.'
"But Burgess says no, that's not the name. And when the man went away he waited a while, and then knocked at the door opposite. The person who opened in answer to the knock was a middle-aged man, stout and with grayish hair. Burgess says he was enough like the description we had of Karkowsky to be his twin brother."