Sen. John Cornyn of Texas introduced legislation on Tuesday that would strengthen background check systems after the mass murder at a Texas church killed 26 people. Devin Kelley was able to purchase the guns used in the shooting after the Air Force failed to inform the FBI that he had been court-martialed and convicted of assaulting his wife and stepson in 2012. Cornyn said the legislation would encourage federal agencies to more efficiently upload required criminal conviction records into the National Instant Criminal Background Check System. “We need to study the whole puzzle, ask ourselves how did this happen,” the GOP senator said. “Why so many lives were lost and what if anything could have been done to prevent it.” Later Tuesday, Sens. Jeff Flake (R-AZ) and Martin Heinrich (D-NM) announced they would introduce legislation aimed at preventing individuals convicted of domestic violence from buying a firearm.