Two Mass Shootings Rock Nation; Interview With Presidential Candidate Julian Castro; Interview With Mayor of South Bend, Indiana, Pete Buttigieg; Interview With Presidential Candidate Beto O'Rourke; Interview With Sen. Cory Booker (D-NJ); Interview With Sen. Sherrod Brown (D-OH); 13 Hours Of Bloodshed, 29 Dead In Two Mass Shooting; At Least Nine Dead, 27 Injured In Dayton Mass Shooting; Interview with Mayor Dee Margo on El Paso Mass Shooting. Aired 9-11a ET