Who else should I visit?

Hint 1 of 17:

As always, visiting the scene of the crime, Mason's house, will do you good.

Hint 2 of 17:

You'll find out that Oswald's wife is staying with Dahlia Farmer.  See her.

Hint 3 of 17:

You will probably want to see anyone who was connected with the work that
Mason was doing for the Bank of England.

Hint 4 of 17:

Those places include The Treasury (not Mainquist's home) and the Bank of
England.

Hint 5 of 17:

Lionel Foxcroft also has some information.  But you'll really want to follow
up on the leads in Oswald's desk.

Hint 6 of 17:

Those are Aberdeen Navigation, Langham Hotel, and Evenson & Co.

Hint 7 of 17:

A statue was sent to Mabel Brown.  See her.

Hint 8 of 17:

You may want to learn more about those Venus de Milo statues.

Hint 9 of 17:

Go to Aggie Small (the business) to see the woman who sells them.

Hint 10 of 17:

The British Museum also sold a few statues.  Go there.

Hint 11 of 17:

Wasn't there a big deal about Jonathan Small and his friends a few years ago?

Hint 12 of 17:

They were accused of stealing the De Vries Diamonds.  Go to them.

Hint 13 of 17:

Jon Small also used to hang out at the Red Bull In.

Hint 14 of 17:

Nat Cook was one of Smith's friends.  He's in Millbank Prison.