“That is just the question, mon ami . Whalley says plainly enough in his letter that the Big Four are on his track, and we know, you and I, that the Big Four is no bogey for the children. Yet everything seems to say that this man Grant committed the crime. Why did he do so? For the sake of the little jade figures? Or is he an agent of the Big Four? I confess that this last seems more likely. However valuable the jade, a man of that class was not likely to realize the fact⁠—at any rate, not to the point of committing murder for them. (That, par example , ought to have struck the Inspector.) He could have stolen the jade and made off with it instead of committing a brutal murder. Ah, yes; I fear our Devonshire friend has not used his little grey cells. He has measured footprints, and has omitted to reflect and arrange his ideas with the necessary order and method.”