The Air Force says it failed to follow policies for alerting federal law enforcement about Devin P. Kelley's violent past, enabling the former service member, who killed at least 26 churchgoers Sunday in Sutherland Springs, Texas, to obtain firearms before the shooting rampage.Kelley should have been barred from purchasing firearms and body armor because of his domestic violence conviction in 2014 while serving at Holloman Air Force Base in New Mexico.