"Either they know exactly where that ivory is, or they haven't the slightest idea." "My, but you're wise!" said Will.
Monty ignored him.

"They suspect us of knowing.

They mean to prevent our getting any of it.

If they do know, they've some reason of their own for not getting it themselves at present.

If they don't know, they suspect we know and intend to claim what we find." "How should they think we know ?" objected Will.