Does tagging cause violence?

Graffiti can be an artistic expression or a menacing mark of territory. In response to two deaths allegedly triggered by tagging wars in 2011, youth at The Know wrote about the connection between tagging and violence and interviewed an artist, a teacher, participants in a community graffiti clean-up for this video and a mother who witnessed a gang-related stabbing: "They don't even know how to spell their own name before they try to write something else."[vimeo http://vimeo.com/26784681 &w=320&h=240]