It's being reported as a possible "town vs. gown" conflict:
Fatal stabbing of UC Berkeley student reveals two worlds within one city - Los Angeles Times
Excerpt:
"Although details of the fracas early Saturday were still being sorted out, the incident laid bare the two faces of this college town on San Francisco Bay -- the world-class university and multimillion-dollar hillside homes with sweeping views versus the poor and working-class bungalows and apartments of the flatlands."