Strategic bombers, submarines have recently operated off Korean coast.
Authorities say Devin Patrick Kelly opened fire in church, killing 26.
Air Force didn’t submit Devin Patrick Kelley’s criminal history to federal database
Devin Kelley served 12 months’ confinement after a 2012 court-martial.
Devin Kelley was discharged from Air Force.
Marine General asked for patience as the military continues to investigate the incident.