How does the mockingbird represent Tom Robinson Jem and Scout walking home from the pageant in To Kill a Mockingbird?

Tom Robinson was innocent in the whole case, even though he was "proven" guilty. Even though he was killed because he was trying to escape jail, he shouldn't have even been in there in a first place. He was as innocent as can be, and nobody would realize the truth. Also, when Scout and Jem are attacked when walking home, Boo is the true one that killed Bob Ewell (not Jem). The whole conversation with Heck Tate and Atticus ends up in a solution to just say Bob fell on the knife. After seeing how Boo has been helping out Jem and Scout over the years, they realized that Boo is actually a very kind-hearted person. Therefore, it would be a sin to say that Boo killed him (it would result in Boo getting killed himself), because Boo was just protecting the kids. Hope this helps. This really is an amazing book :)