"Being a criminal novice, he doesn't know any regular receiver of stolen goods, and if he did would prefer to wait and get full value by an ordinary sale. There will always be a danger of detection so long as the stones are not securely hidden, so he proceeds to hide them. He knows that if any suspicion were aroused his rooms would be searched in every likely place, so he looks for an unlikely place. Of course, he thinks of taking out a panel and hiding them behind that. But the idea is so obvious that it won't do; the police would certainly take those panels out to look behind them. Therefore he determines to hide them _in_ the panels. See here--he took the two pieces of wood with the filled hole from his tail pocket and opened his penknife--the putty near the surface is softer than that near the bottom of the hole; two different lots of putty, differently mixed, perhaps, have been used, therefore, presumably, at different times." "But to return to Challitt. He makes holes with a centre-bit in different places on the panels, and in each hole he places a diamond, embedding it carefully in putty. He smooths the surface carefully flush with the wood, and then very carefully paints the place over, shading off the paint at the edges so as to leave no signs of a patch. He doesn't do the whole job at once, creating a noise and a smell of paint, but keeps on steadily, a few holes at a time, till in a little while the whole wainscoting is set with hidden diamonds, and every panel is apparently sound and whole." "But, then--there was only one such hole in the whole lot." "Just so, and that very circumstance tells us the whole truth. Let me tell the story first--I'll explain the clue after. The diamonds lie hidden for a few months--he grows impatient. He wants the money, and he can't see a way of getting it. At last he determines to make a bolt and go abroad to sell his plunder. He knows he will want money for expenses, and that he may not be able to get rid of his diamonds at once. He also expects that his suddenly going abroad while the robbery is still in people's minds will bring suspicion on him in any case, so, in for a penny in for a pound, he commits a bold forgery, which, had it been successful, would have put him in funds and enabled him to leave the country with the stones. But the forgery is detected, and he is haled to prison, leaving the diamonds in their wainscot setting.