"I quite agree. Even cumulative proof may be destroyed. I can guess what you are half thinking. You believe that I've fastened my suspicions on Grell, and that I'm determined to go through with it right or wrong. That's a common mistake people fall into in regard to police functions. In fact, it doesn't matter a bit to a police official whether he gets a conviction or not--unless, of course, he neglects an important piece of proof through gross carelessness. All he has to do is to solve a problem and to place his answer before a magistrate, and then a judge and jury to decide whether he's right or wrong. No one but a fool would attempt to bolster up a wrong answer. In this case, too, you must remember that there are finger-prints. They cannot lie. If we get the right man--Grell or any one else--there will be no question of doubt." Fairfield tapped a cigarette on the back of his left hand and rose. "Well, even if you do draw Grell with that advertisement, I doubt if you'll get anything from him if he doesn't want to talk. I know the man, and he's hard to beat out of any decision that he makes up his mind to, as hard"--he bowed smilingly to the detective--"as you would be." "Thank you. If it were a question of Grell against Foyle I might have to go under. But it isn't. Behind me is the C.I.D., behind that the whole force, behind that the Home Secretary, and behind him the State. So you see the odds are on my side." A jerky buzz at the telephone behind the superintendent's desk interrupted any reply that Fairfield might have made. With a muttered "Good-day" the baronet moved across the carpeted floor out of the room. As he closed the door Foyle put the receiver to his ear. "Hello! Hello!... Yes, this is Foyle speaking. Oh yes, I know.... No, you'd better not tell me over the telephone. You can't come here. Somebody who knows you might see you.... Is it important?... All right. You'd better come to Lyon's tea-place in the Strand--the one nearest Trafalgar Square. I'll get Mr. Green to go along and have a talk with you. Good-bye." Rubbing his hands together thoughtfully, the superintendent sent for Green. In a few moments the big figure of the chief inspector loomed in the doorway. "Dutch Fred thinks he's got hold of something," opened Foyle abruptly. "I've told him to meet you at Lyon's in the Strand. I think he's all right, but don't let him have any money until you've tested his yarn." "Very good, sir," said Green. "I'll look into it."