Authorities say Shamar Elkins, a 31-year-old Louisiana National Guard veteran, carried out the mass shooting that killed seven of his own children and their cousin in Shreveport after a domestic dispute, before carjacking a vehicle and leading police on a chase. Officials say Elkins later killed himself in the driveway of his former Army mentor’s home, as investigators continue probing how he obtained the firearm despite a prior felony conviction.