Doonesbury by Garry Trudeau for June 25, 1973
Transcript:
Man: Well, if you really want to know, little brother, it was over a card game... this cat cheated me - but good! I lost my temper and blew his head off! Man, was I mad with that dude! Really mad! Actually, I feel kinda bad about it now... Zonker: Natch! That's what prison's about!