I told him what I thought. This type of person would have a house on the Avenue; it would be closed in August. Walker shook his head. “I think I know where they have gone,” he said. Again I looked at him in astonishment. “Then you know who this man is?” Walker replied with an abrupt query: “Did you see the inside of his hand—the right hand? That was the thing to see.” “How about the girl?” I replied, for Walker’s indirections were putting me on my mettle. “Her hand will be the thing to see; it’s got Bartoldi’s diamond on it.” He looked up rather vaguely. “I am puzzled about the girl; I do not understand what the girl has to do with it.” I laughed. “Bartoldi understood,” I said. “Bartoldi!” Walker seemed to bounce out of his reflection. “The devil! We’ve got to get back his diamond.” He darted suddenly out to the traffic of the Avenue, hailed a taxicab and beckoned me to get in with him. I got in and we went up Fifth Avenue. We were held in a jam of vehicles a block or two farther on. “And so,” I said, “you think the girl is a nice little country cousin, an esteemed relative—esteemed to the tune of a five-thousand-dollar diamond?” Walker was fingering his face in reflection. “Nonsense!” he said. “The girl’s no relation to him.” “Then why the five-thousand-dollar diamond?” “That’s what I would like to know,” said Walker. I laughed. The thing was too absurd. “If the wage of a sin is a five-thousand-dollar diamond, there’s got to be the sin to earn it. That old sport was not taking any chance on getting the value of his money.” “O. K.,” said Walker. “Then you think he has been paid for it?” I said. “Surely,” said Walker, “that man has been paid for it.” The taxicab turned out of the Avenue presently when the jam of vehicles was released, and stopped before the Grand Central Station. Walker paused a moment when we got down. “If I put the thing together correctly,” he said, “they will be here. The girl came in for her diamond.... How she earned it puzzles me.... The man had to get through with it as quickly as he could.” He made a little gesture. “From the station to Bartoldi’s in a taxicab and back to the first train out—that would be his plan—to hurry.” He added: “It was a risk, a big risk. But he had to take it. He couldn’t trust anybody; he had to do it himself.” I looked at Walker with what I imagined was an ironical smile. “Then he would not be guilty under the statute,” I said, “for he only brought the little baggage in to buy her a diamond.” Walker seemed in a sort of reflection. “Oh, yes,” he said, “he is guilty.” “Then you want him?” I asked. Walker suddenly looked at me with his eyes wide. “Surely,” he said. “Then why don’t you hurry?” I demanded. He looked at me with a leisurely interest. “If he’s here,” he said, “he can’t get out. I’ve got three of the best agents of the Department in there—sent them up when I started to Bartoldi’s to meet you.” “But how would they know him?” I asked.