COLORADO SPRINGS, Colo. — Two of the four guns used in the church shooting in Texas on Sunday were purchased in Colorado, officials said Monday.

However, officials did not say where in Colorado the guns were purchased. The other two guns were purchased in Texas.

Paul Paradis owns Paradise Sales, a gun store in Colorado Springs. He didn’t sell the shooter any of the weapons used in the massacre, but he said he empathizes with the gun store owner who did.

On Monday, it was revealed the Air Force didn’t submit 26 year-old Devin Patrick Kelley’s criminal history to the FBI.

Paradis said he isn’t surprised that happened.

“We’ve seen similar problems in the past so it’s not terribly unusual,” he said. “Everything we have is run by humans and humans create error.”

Paradis said he’s seen other criminals somehow pass background checks, and he said he’s even unknowingly sold guns used in crimes.

“It’s happened to me before. Does it make you feel good? No. You wonder if there is something I could have done,” Paradis said.

“I’ve been in that position, having some of those sleepless nights. I can tell you that you look back and say I did everything I could reasonably do.”

However, a Colorado gun control group is less willing to move past the Air Force’s mistake.

“It does make me wonder if there is a loophole in the system,” said Tom Mauser with Colorado Ceasefire. “Clearly there is a mechanism for reporting domestic violence in the civilian world. Does it work on the military side also?” he said.

It’s a question at the forefront of the investigation as the Air Force launches an internal review into why the suspect’s criminal history was never passed along.