From Live Leak:
"I don't know the back story, and don't really care. Kudos to this Dallas (TX) officer for keeping his cool and a special shoutout to the citizen sheepdog that braved a potentially violent, racist crowd to help the officer. More of people like him, please"
Read more at http://www.liveleak.com/view?i=72d_1432478920#qloq4ju3lT9yOUMr.99