In chapter 10, the file that belonged to Joe which Pip stole for the convict reappears. There is a man sitting at the bar at the Three Jolly Bargemen who is actually stirring a drink with the file. He keeps looking at Pip and Pip notices with great astonishment. He might have felt remorse and shame and surprise all at once. Upon the departure of this man, he crumples up and leaves a two-pound note.
In chapter 16, a leg-iron is found next to Mrs. Joe's bed. This is found after she had been struck and seriously injured. It looks like the item was placed as a message to say that someone who may have been a convict hurt her. But, with Joe being an expert in metalworks, he was able to quickly determine that it had been filed off a long time ago. This convinces Pip that it could be the iron leg of the convict, his convict.
Both items have the convict in common and leave Pip feeling unsettled and unknowing about why they are where they are.