When you arrive at 'Tavistock Train Station' in Dartmoor, go one east and ASK POLICEMAN SELDEN
He tells you about the escaped murderer Harry Selden, who escaped and is hiding out on the moors.
He'll ask if you're interested in arresting him. ASK POLICEMAN ARREST and he'll give you a pair of manacles.
Go to 'A Comfortable House' which is east of 'A Provincial Marketplace'
ASK MORTIMERY SELDEN, and he'll tell you that Mrs. Barrymore, the stewardess at Baskerville Hall's maiden name was Selden.
Go to 'Baskerville Hall' and ASK BARRYMORE SELDEN and she'll tell you about her brother, the murderer, who came to her for help and who is hiding out on the moors. She'll give you a bowl of potato soup.
With this in your inventory, go to the ruined sheepfold, EESSSE of Baskerville Hall.
Harry Selden will take the soup out of your inventory, and ask what you want.
GIVE MANACLES HARRY, and he'll attack you.
Beat him til he's dying and he'll surrender, then GIVE MANACLES HARRY and you'll receive XP and the whois.