'What an evil man!' I said. 'But she did not want to help Stapleton. She tried to warn both of them, didn't she?'
'Yes, she tried to meet Sir Charles the night he died. But Stapleton found out. Stapleton waited for Charles and frightened him to death with the dog. Also Stapleton sent the note to Sir Henry at the Northumberland Hotel. Then Sir Henry fell in love with Mrs. Stapleton, so Stapleton was worried and angry. At last, Stapleton had to tie her up to stop her telling Sir Henry.'
'And Stapleton was the man with the black beard?'
'Yes, he tried to hide his face. He put on beard when he followed Sir Henry in London.'
'What about the missing boots?' I asked.
'The dog and the boots go together,' Holmes said. 'Stapleton knew the silly story about the Hound of the Baskervilles. And he knew that Sir Charles believed the story. So, Stapleton bought that huge black dog and let it walk on the moor at night.'
'But the boots,' I said. 'What about the stolen boots?'
'Watson, you are very slow,' said Holmes. 'It was a hunting dog Hunting dogs will follow a smell. Stapleton wanted some of Sir Henry's clothes to give to the dog. he paid a waiter at the hotel to steal the boots. But the first boot did not work because it was new. It did not have Sir Henry's smell.