It's since been deleted (of course), and the Atlanta Journal-Constitution has yet to offer an apology or an explanation, but some announcement about their account being hacked will probably hit the Twitter machine any moment now.
Update: And here's the apology.
The AJC apologizes for & deeply regrets the tweet that was posted earlier today. We are working to address this situation internally.
— AJC (@ajc) October 23, 2013
[screengrab via Brian Floyd]