In Harper Lee's To Kill a Mockingbird, one time in which Sheriff Heck Tate speaks directly of Tom Robinson, he expresses his guilt for having made Robinson's arrest, which precipitated Robinson's unjust death.
During Robinson's trial, Atticus had convinced Sheriff Tate of Robinson's innocence by making Sheriff Tate realize it would have been impossible for Robinson to bruise Mayella Ewell in her right eye when he is crippled in both his left arm and hand.
By Chapter 30, Sheriff Tate expresses his guilt over having arrested Robinson. In this chapter, Scout and Jem have just been rescued from Bob Ewell, and Atticus has stated his belief that Jem was responsible for Ewell's death, believing the matter should be brought to court. Sheriff Taylor, knowing that Arthur Radley actually killed Ewell in defense of the children, tries to convince Atticus to let the matter drop because Sheriff Tate sees how immoral it would be to bring Arthur out into the limelight, bringing him to trial, simply for saving the lives of Atticus's children. Thinking about this immorality makes Sheriff Tate reflect on his earlier immoral deed of wrongfully and prejudicially arresting Robinson. By way of confession, he tells Atticus that he may not be a "very good man," but, as sheriff, he knows the right thing to do, which is leave Ewell's death alone since Ewell has now received his just deserts for causing the unjust death of Robinson:
There's a black boy dead for no reason, and the man responsible for it's dead. Let the dead bury the dead this time, Mr. Finch. Let the dead bury the dead.
In speaking of a "black boy dead," Sheriff Tate is referring to Robinson, whose death Ewell is responsible for. The fact that Sheriff Tate thinks Ewell is responsible for Robinson's death, rather than thinking Robinson's own criminal actions caused his death, shows us Sheriff Tate now sees Robinson as innocent and feels guilty for having made the arrest that led to Robinson's death.