A gunman has killed six people in drive-by shootings in the Californian city of Santa Barbara, Friday night.
The shootings took place near the University of California-Santa Barbara, where two-thirds of the residents are students, the BBC reports.
Seven more people were wounded late on Friday in the town of Isla Vista near the campus of the University.
The documentary was filmed in a number of locations, including Oakland, California, Santa Fe, New Mexico and Chicago, Illinois. The filmmakers also visited a number of sites in Colorado, where the Ludlow Massacre took place. These included Denver, Fort Collins and Colorado Springs.
By Nick Malkoutzis