The United States remains on edge after its latest high-profile mass shooting on July 4th in Highland Park, Illinois, which resulted in the killing of 7 people, leaving many more injured. Stories like these beg the question - what are the motivations for these acts of violence? Plus, at least two immigrant detainees have been held in solitary confinement for about a week at the for-profit private facility where they are locked up in Bakersfield. The men and their attorney's say it's retaliation for supporting a peaceful labor strike. This weekend in the arts: Southern gothic blues at the Casbah, a last chance to see improv hip hop at The Old Globe and the Barrio Art Crawl.