Lennie went back and looked at the dead girl. The puppy lay close to her. Lennie picked it up. “I’ll throw him away,” he said. “It’s bad enough like it is.”
– John Steinbeck
Of Mice and Men, Chapter 5. After shaking Curley’s wife so hard that he breaks her neck, Lennie knows he has done a bad thing. But he actually thinks it will make it look better if he throws away the puppy.