“No, there is no news of Felling, and Brown, who is a much more difficult proposition, has disappeared from view. Why is he more difficult? Because he is unknown. In comparison, tracing Walters is child’s play. Yet we haven’t even found him,” said the inspector wiping his face, “which is rather surprising, considering that we know his usual haunts and acquaintances. None of these say they have seen him. The cab-driver has come forward in answer to our hurry up call, and says he set down Felling at the Central Station. They stopped on the way to buy a hat, apparently.” Carver had not been to the station that morning and even if he had, he could not have given the news which was to startle Tab later in the day. “Have you formed any fresh theory, Carver?” Carver looked out of the window and pulled his long nose thoughtfully. He was a tall thin man with a lean face that was all lines and furrows. In repose it was melancholy in the extreme, and his gentle apologetic tone seemed somehow in keeping with his appearance. “There are several theories, all more or less fluid,” he said. “Has it occurred to you,” asked Tab, “that the shot might have been fired through one of the ventilator holes?” Carver nodded several times before he answered. “It occurred to me after I left you and I went back to make sure, but there was no blackening of the grating such as there would be if a pistol of sufficient small calibre had been pressed against one of the holes and fired, added to which, there is this important fact, that the bullet of the size the doctors found in Trasmere’s body would not go through any such hole.” Carver shook his head. “No, the murder was committed actually in the vault, either by Brown, by Walters or by some third person.” Tab had a few independent enquiries to pursue, one of which related to the cook. She had already been questioned by the police, he discovered, when he reached her little suburban home. A quiet, motherly and unimaginative woman, there was little she could tell him. “It was my day off,” she said. “Mr. Trasmere said he was going into the country, though I don’t suppose he was. He had said that before, but Walters told me to take no notice. I have never seen Mr. Trasmere,” she said, to Tab’s surprise. “All my orders came through Mr. Walters, and practically I was never inside the house except once, when the cleaning woman did not turn up in the morning and I helped Walters to tidy the master’s sitting-room. I remember that morning because I found a little black lid--well it was hardly a lid, I have got it here if you would like to see it. I have often wondered what it was for.” “Lid,” said Tab. “What kind of a lid?” “It was like the lid of a small pill-box,” explained the woman, “about the size of a threepenny piece. I picked it up and asked Mr. Walters what it was for, and he said he didn’t know. It was on the floor near the table and I brought it home, meaning to ask my husband what it was.”