“Anything wrong, sir?”

“No, not exactly. You understand what has to be done with Mills? He is to see nobody. Immediately he arrives he is to be put into the waiting-room—alone. There is to be no conversation of any kind, and, if he speaks, he is not to be answered.”

In the privacy of his office he inspected his find again. Everything was there—the treaty and Lord Farmley’s notes. Elk called up his lordship and told the good news. Later came a small deputation from the Foreign Office to collect the precious document, and to offer, in the name of the Ministry, their thanks for his services in recovering the lost papers. All of which Elk accepted graciously. He would have been cursed with as great heartiness if he had failed, and would have been equally innocent of responsibility.

He had arranged for Mills to be brought to Headquarters at noon. There remained an hour to be filled, and he spent that hour unprofitably in a rough interrogation of Hagn, who, stripped of his beard, occupied a special cell segregated from the ordinary places of confinement in Cannon Row Station—which is virtually Scotland Yard itself.

Hagn refused to make any statement—even when formally charged with the murder of Inspector Genter. He did, however, make a comment on the charge when Elk saw him this morning.

“You have no proof, Elk,” he said, “and you know that I am innocent.”

“You were the last man seen in Genter’s company,” said Elk sternly. “It is established that you brought his body back to town. In addition to which, Mills has spilt everything.”

“I’m aware what Mills has said,” remarked the other.

“You’re not so aware either,” suggested Elk. “And now I’ll tell you something: we’ve had Number Seven under lock and key since morning—now laugh!”

To his amazement the man’s face relaxed in a broad grin.