He was glad to have spoken to her, because he had recognized at once the immense importance of her evidence. To the Inspector no doubt it had seemed only of importance in that it had shown Mark to have adopted something of a threatening attitude towards his brother. To Antony it had much more significance. It was the only trustworthy evidence that Mark had been in the office at all that afternoon.

For who saw Mark go into the office? Only Cayley. And if Cayley had been hiding the truth about the keys, why should he not be hiding the truth about Mark’s entry into the office? Obviously all Cayley’s evidence went for nothing. Some of it no doubt was true; but he was giving it, both truth and falsehood, with a purpose. What the purpose was Antony did not know as yet⁠—to shield Mark, to shield himself⁠—even to betray Mark⁠—it might be any of these. But since his evidence was given for his own ends, it was impossible that it could be treated as the evidence of an impartial and trustworthy onlooker. Such, for instance, as Elsie appeared to be.