Why did Silas suspect Jem Rodney?

Answer 1

When Silas finds that his money is gone and he has been robbed he thinks of the list of the neighbours who could steal his money. From the list comes Jem Rodney, a known poacher who had often met Silas in the fields and said something jestingly about the weaver's (Silas's) money. Also Jem often had gone to Silas's cottage than anyone else.