How does steinbeck's characterization of lennie develop a theme of violence?

When the novel opens Lennie is being hunted for what was called an attempted rape. We then see him kill various creature because he succumbs to his desire to touch and pet soft things. Lennie does not act violently, he does not understand what he is doing. At the end of the novel Lennie has killed his puppywith love, then soon afterward Curly's wife out of fear.