Sir Angus had sent some one down to York to see this gentleman, but nothing of further value had been elicited, excepting, yes, that the lady had struck him as being young and attractive. So it was that the extraordinary typewritten letter received by Mrs. Pavely that morning very much upset the calculations and the theories of Sir Angus and of his staff. With frowning brow he sat down at his table and touched the electric bell which lay concealed close to his hand. "Ask Mr. Dowden to come to me," and a minute later Mr. Dowden came in. "I want to know anything you can tell me about Duke House, if indeed there is such a place as Duke House in Piccadilly. I can't remember the name." But at once the other answered: "It's that big new building they've erected on the site of St. Andrews House. It fell in to the Crown on the death of the Duke of St. Andrews, and an American syndicate bought the site. Duke House, as they call it, was only opened last October. The lower storeys are big bachelor flats, and the top half of the building contains offices. Mr. Biddle, the American millionaire, has taken the first floor, but he hasn't settled in yet, and I don't think any of the offices have been let at all. They are asking very big rents, and they are justified, as it's one of the finest sites in the West End." "I want you to get through to the porter of Duke House. Find out for me whether they have got an office let to a man--a Portuguese merchant I take him to be, of the name of Fernando Apra." He spelt out the name. "If you have any difficulty in getting the information, just go up there yourself in a taxi, and find out. But I'd like you to go back into your own rooms and try by telephone first." There followed a long, painful ten minutes, during which Sir Angus, though as a rule he was a man of few words, tried to while away the time by explaining to the three people who were there why he thought it unlikely that the letter was genuine. "You'd be amazed," he said, "to know the number of letters we receive purporting to contain important information which turn out to be false in every particular. There must be a whole breed of individuals who spend their time in writing annoying, futile letters, which, even if signed, are very seldom signed by the writer's real name. Some of those people are actuated by vulgar, stupid spite; others are hypnotised by the thought of a reward. And then, again, such letters are often written by people who have a grudge against the police, or, even more often, by some one who has a grudge against some ordinary person who has, maybe, done them a bad turn, or to whom they have done a bad turn! In the last few days we've had innumerable letters, from all over the kingdom, concerning Mr. Pavely's disappearance. It is just possible that this man"--he looked down again at the sheet of typewritten paper--"has an office in Duke House, but I think it very unlikely that Mr. Godfrey Pavely was even acquainted with him----"