Campus Guardian Angel demonstrated its technology that uses drones to confront and to respond to school shooters while law enforcement is still on the way. News4’s Mauricio Casillas reports.⁠ ⁠ #washingtondc #maryland #virginia #pgcounty #dc #districtofcolumbia #dmv #northernvirginia #alexandriava #northernva #arlingtonva #fairfaxcounty #nova #md #mocomd #pgcountymd #drones