The theme of "man inhumanity to man" is centralto this novel. Where can this theme be seen in the novel?

Certainly the treatment of blacks as slaves. We see this up close and personal with Jim. All he wants to do is get back to his family but he is owned and sold by whites. WE also see white attitudes to each other. The Duke and King, seemingly benign old men, are actually conniving and cruel. Huck sees this inhumanity and decides to have none of it.