– The man who opened fire on a rural church outside of San Antonio on Sunday, killing 26 worshipers and wounding 20 more, did not have a license to carry a gun in Texas, authorities said Monday.

The gunman, Devin Patrick Kelley, 26, of New Braunfels, Texas, had purchased four guns over the past four years, two in Texas and two in Colorado.

Authorities are trying to determine how Kelley, who was court-martialed by the military after abusing his wife and child, got his hands on the weapons. He received a bad-conduct discharge from the Air Force in 2014.

The military on Monday acknowledged that it did not submit the shooter's criminal history to the FBI, as required by the Pentagon. If his offenses had been properly shared, they would have prevented him from buying a gun.

In an interview on CBS News, Texas Gov. Greg Abbott described Kelley as "someone who was a powder keg seemingly waiting to go off."

"Under current law, he should have been prevented from making this purchase," Abbott said. "How that got through the cracks, I don't have that information."

Kelley walked into the First Baptist Church in Sutherland Springs and opened fire in what is the deadliest mass shooting in Texas history.

Texas Department of Public Safety spokesman Tom Vinger said Kelley did not have a license to carry in Texas.

DPS officials giving updates on the case Monday morning said Kelley bought four guns — one a year from 2014 to 2017.

Three weapons were recovered after Sunday's shooting.

Two handguns — a Ruger .22 and a Glock 9mm — were found in Kelley's car. And a Ruger AR-556 rifle was found at the church, Texas Department of Public Safety Regional Director Freeman Martin said.

There are several reasons people might be rejected from buying a gun, including if they are a fugitive, committed to a mental institution, unlawfully in the country — or if they have "been discharged from the Armed Forces under dishonorable conditions," according to the National Instant Criminal Background Check System.

But Kelley wasn't dishonorably discharged from the Air Force.

A bad-conduct discharge is not as severe as a dishonorable discharge.