Tab smiled to himself. He who had investigated so many burglaries had never imagined that he would be favoured by the attention of those midnight adventurers. He went into Rex’s room, turned the switch and had only to take one glance to know that somebody had been very busy indeed in his absence. Under the bed which his companion had occupied, were two shallow trunks, filled with those of Rex Lander’s belongings which he had not taken with him. One of these had been pulled out, placed on the bed and opened. It had been opened unscientifically with a chisel, which Tab knew was his property, and must have been taken from the tool-box in the kitchen. The lock was wrenched off and the contents of the box were scattered on the bed. The other trunk had not been touched. Whether the thief had been successful in his quest Tab did not know, because he was ignorant of the box’s contents. He guessed he must have been disappointed, for beyond a quantity of underlinen, more or less in a state of disrepair, a few books and drawing instruments, and a packet of letters which Tab saw at a glance were from Jesse Trasmere, there was nothing at all valuable in the trunk. He went to his own room, but none of his things had been touched. And then he began a careful search of the other rooms in the flat. They yielded, however, no clue as to the identity of the mysterious visitor, and Tab got on to the ’phone to Carver and was lucky to find him. “Burglars? That’s poetic justice, Tab,” said Carver’s sad voice. “I’ll come right along.” The detective was at the house in ten minutes. “If this had happened in the daytime I could find a fairly simple explanation,” said Tab, “because the front door below is left open until nine, and the tenant who comes in or goes out nearest to nine o’clock, closes it. We keep the door open because it saves a lot of running up and down stairs, but the street-door was closed when I came home.” “How would it have been a simple matter to burgle the flat?” asked Carver, and Tab explained that there was a window on the landing through which a sure-footed and skilful adventurer might emerge on to a narrow ledge by which the kitchen window could be reached. “He didn’t go that way I should think,” said Carver, after he had inspected the kitchenette. “No, the burglar opened the door like a gentleman. Do you know whether Mr. Lander had anything worth stealing in that trunk?” Tab shook his head. “I am perfectly certain he hadn’t,” he said. “Poor old Rex had nothing of value except the money he drew from his uncle’s estate just before he left.” Carver went back to Rex’s room and carefully emptied the trunk item by item. “It was something at the bottom of the trunk. I should imagine it was in this box.” He handled a little wooden box with a sliding lid. “And here is the top,” he said, picking it up from the bed. “Can you get in touch with Mr. Lander?”