Von Behrling has that packet in his possession.

When I come to see you in London, I will bring you twenty thousand pounds in Bank of England notes.

With that Von Behrling might fancy himself on his way to America--with you." She closed her eyes for a moment.

Perhaps she wished to keep hidden from him the thoughts which chased one another through her brain.
He wished to make use of her--of her, the woman whom he loved.
Then she remembered that it was for her country and his, and the anger passed.
"But I am afraid," she said softly, "that the moment they reach London this document will be taken to the Austrian Embassy." "Before then," Bellamy declared, "Von Behrling must not know whether he is in heaven or upon earth.

It will not be opened in London.
He can make up another packet to resemble precisely the one of which he robbed Dorward.