“You may be very sure we shall go into the matter thoroughly,” replied the Chief. “It is a serious business. But I cannot promise to put any particular man on the investigation. You may be sure, however, that you will have a fair deal and that we will get to the bottom of the affair.” Willie went away, feeling that his effort had been in vain. It was, however, more fruitful than he ever dreamed it would be. The first Secret Service operative questioned others besides Willie, and at once everybody in the office knew him for what he was. Thereafter his usefulness was past. The Chief recalled him and sent a second operative: and the new man was Sheridan. But no one knew he was a Secret Service man. He came into the building as a cleaner and porter; and even Willie would not have known him had he seen him. For a long time he made no more headway than did Willie, who was industriously communicating, day after day, with wireless operators, in a quest for some one who had heard his signals on the day the papers were stolen from the Special Agent’s desk. But apparently the quest was vain. Meanwhile Willie did his work with absolute fidelity, putting into it every bit of mind and energy he possessed. But he could see that he was watched on all sides, and that belief in his guilt did not lessen as time passed. CHAPTER XI WILLIE MAKES A DISCOVERY But though Willie made no headway in his investigation, he was making splendid progress with his other work. He was on his mettle now. He had but one thought, night and day. That was to prove his worth. That meant, first, to prove his innocence; and second, to prove his ability. Time might or might not show who really took the papers. Willie, seemingly, could do nothing to clarify the situation. But to attain his other ends, he could do everything. He began to study his various tasks, to see if there were better or more efficient ways of doing them. He tried harder and harder to be efficient at the gate, to keep things running smoothly, to do all he could to help forward the business of the office. Very quickly he learned where all the various supplies were. He soon knew the ins and outs of the entire place. He knew all the offices in the huge building, and could tell offhand who were in charge of them. And while he thus became more useful, he was absorbing information that was to make him more useful still. Day after day, the operatives or special agents who worked with the customs inspectors to prevent smuggling, came in and discussed their cases. Willie often heard much that they said. So he came to know the names of persons who had tried to smuggle in goods, the methods they resorted to, and the artifices employed to trap them.