LITTLETON, Colo. — A Colorado gun control group said the biggest question hanging over the deadly Texas church shooting is how the gunman legally purchased his weapons.

The Texas Department of Public Safety said Devin Kelley was able to purchase four guns between 2014 and 2017 — two in Colorado and two in Texas.

What’s significant is that all of those purchases took place after Kelley had been court-martialed from the Air Force for domestic violence, received a reduction in rank and was discharged for bad conduct.

Under military rules, any person who receives a dishonorable discharge is prohibited from purchasing a firearm.

While Kelley was not dishonorably discharged, Colorado Ceasefire said as long as his military conviction was for domestic violence, he still shouldn’t have been able to purchase a weapon.

“Even in the military world you cannot purchase in the case of domestic violence, but it has to be reported into the system,” said Tom Mauser with Colorado Ceasefire. “I’m wondering if it was reported into the system?”

When Kelley bought his semiautomatic Ruger rifle at a San Antonio sports store in 2016, the NICS background check presumably came back clean.

Officials tell The Associated Press that the Air Force did not submit Kelley’s criminal history to the FBI, as required by Pentagon rules.

“It does make me wonder if there is a loophole in the system. Clearly, there is a mechanism for reporting domestic violence in the civilian world. Does it work on the military side also?” said Mauser, whose 15-year son Daniel was killed during the Columbine school shooting in 1999.

Mauser said Kelley was denied a conceal carry permit in Texas but somehow wasn’t denied a gun purchase in either Colorado or Texas.

“It’s not often that you’re denied a conceal carry permit without cause. Well what was the cause?” Mauser said.

Texas authorities have yet to clarify why Kelley was denied a conceal carry permit at the time of his application.

“What I will tell you right now is that in general if an individual has a dishonorable discharge from the military they would be prohibited from possessing or purchasing firearms,” said Freeman Martin, the regional director for the Texas Department of Public Safety.

“In this specific investigation, we are early in the investigation. We do not have all the documentation in yet so until we get all the documentation to determine exactly what his discharge was exactly,  was his conviction in the military,  we will not have a determination of this individual prohibition from purchasing or possessing a firearm.”