Facebook's Mark Zuckerberg on video killing: 'We have a lot of work to do'

Facebook CEO Mark Zuckerberg briefly addresses on stage the killing of a man in Cleveland that was uploaded to the social network, saying 'we will keep doing all we can to prevent tragedies like this.' Steve Stephens posted a video of the killing of Robert Godwin Sr on Monday. The next day, Stephens killed himself while being pursued by police.