As soon as our cab was started on its way back to Hewitt's office Plummer explained himself.
"He's been watched," he said, "has Mr. Telfer, when he didn't know it; and he'll be watched again for the rest of to-day, as I've arranged. What's more, he won't be allowed to leave the office this evening till I have seen him again, or sent a message. No need to frighten him too soon—it mightn't suit us. But he's in it, alone or in company!"
"How do you know?"
"I'll tell you. It seems the lead roofs are being repaired at the Admiralty, and the plumbers are walking about where they like. Now I needn't tell you I've had a man or two fishing about among the doorkeepers and so on at the Admiralty, and one of them found a plumber he knew slightly, working on the roof. That plumber happens to be no fool—a bit smarter than the detective-constable, it seems to me, in fact. Anyhow, he seems to have got more out of my man than my man got out of him; and soon after I reached the Yard he turned up, asking to see me. He said he'd heard that a valuable paper was missing (he didn't know what) from the room with the skylight in the top floor, where the gentleman with the single eye-glass was, and where the safe was let in the wall; and he wanted to know what would be the reward for anybody giving information about it. Of course I couldn't make any promise, and I gave him to understand that he would have to leave the amount of the reward to the authorities, if his information was worth anything; also, that we were getting to work fast, and that if he wished to be first to give information he'd better be quick about it; but I promised to make a special report of his name and what he had to say if it were useful. And it will be, or I'm vastly mistaken! For just you see here. Our friend, Mr. Telfer, says he put that code safely away at 10.20 in the safe, and that he never went to the safe again till 12.20, when the Controller's secretary was with him; never went to it for anything whatever, observe. Well, the plumber happened to be near the skylight at half-past eleven, and he is prepared to swear that he saw Mr. Telfer—'the gent with the eye-glass,' as he calls him—go to the safe, unlock it, take out a grey paper, folded lengthwise, with red tape round it, re-lock the safe, and carry that paper out into the corridor! The plumber was kneeling by a brazier, it seems, which was close by the skylight, and he is so certain of the time because he was regulating his watch by Westminster Hall clock, and compared it when the half-hour struck, which was just while Telfer was absent in the corridor with the paper. He was only gone a second or two, and you will remember that Corder saw Mayes leaving the premises within two minutes of that time!"
"Yes!"
"Well, Telfer was back in a second or two, without the paper, and went on with his affairs as before. That's pretty striking, eh?"
"Yes," Hewitt answered thoughtfully, "it is."
"It was a sort of shot in the dark on the part of the plumber, for he knew nothing else—nothing about Telfer legitimately having the keys of the safe, nor any of the particulars we have been told. He merely knew that a paper was missing, and having seen a paper taken out of the safe he got it into his head that he had possibly witnessed the theft; and he kept his knowledge to himself till he could see somebody in authority. Mighty keen, too, about a reward!"
"And now you are having Telfer supervised?"
"I am. Not that we're likely to get the code from him; that's passed out, sure enough, in Mayes's hands—or else his pockets."