“Another new pin!” said the detective thoughtfully. “This time, inside!”
A thorough search of the house failed to discover the second man. He must have made his escape just before the police arrived, for the smoke of the pistol’s explosion still hung in the vaulted roof.
When the doctors came and the body was moved Tab spoke what was in his mind.
“Carver, I have been a fool,” he said quietly. “We ought to have been able to prevent this. We should have done it if I had only remembered.”
“What?” asked Carver, arousing himself from thoughts which did not seem to be particularly pleasant, to judge from his expression.
“That key was in Rex’s box. I remember now that he mentioned casually that he put it in his trunk before he went away.”
Carver nodded.
“I guessed that,” he said. “Probably we both arrived at that solution when we saw the key on the table. The burglary of your flat is, of course, explained. He came the first time for the key and was disturbed by the tenant from the flat beneath and got away before it had been found. Tonight, the need being urgent, he took a chance, found the key, and—” he shrugged. “How did the key get on the table? The door was locked both sides, yet there is the key—and the new pin,” he added half to himself, “the second new pin.”
He got up and stretched himself and began to pace up and down old Trasmere’s sitting-room.
“No weapon, nothing but the body—and the new pin,” he mused, half to himself. “This lets out friend Walters, of course; there isn’t a shadow of evidence against him after this second murder. We can hold him for theft on his own confession—but no more. Tab, I am going down to the vault; I don’t want you to come with me. There are one or two things that I want to be certain about.”