The trial of Tom Robinson is of great significance in To Kill a Mockingbird. In the novel, Atticus Finch teaches his children, Scout and Jem, that they are not to shoot mockingbirds, since mockingbirds represent only purity and beauty; the birds do not harm anyone and only give beauty in the form or song. The trial of Tom Robinson is symbolic of the killing of a mockingbird, which is (in turn) symbolic of the destruction of innocence.
Tom Robinson, is found guilty of the rape of Mayella Ewell, despite his actual innocence. The reason for the guilty verdict lies in the prejudice of those around him. As a black man, he is assumed to possess fewer morals and less innate goodness than the white citizens of Maycomb, including Bob Ewell. When Tom Robinson dies as a result of attempting to escape the prison in which he never should have been placed, it is a direct reflection of the theme of the destruction of innocence.