SUTHERLAND SPRINGS, Texas — A day after a gunman massacred parishioner in a small Texas church on Sunday, the Air Force admitted Monday that it had failed to enter the man’s domestic violence court-martial into a federal database that could have prevented him to buy the rifle that he used to kill 26 people in the church.
The conviction of Devin P. Kelley, for domestic assault on his wife and toddler stepson — he had cracked the child’s skull — should have stopped Mr. Kelley from legally purchasing the military-style rifle and three other guns he acquired in the last four years, under the federal law.
“The Air Force has launched a review of how the service handled the criminal records of former Airman Devin P. Kelley following his 2012 domestic violence conviction,” the Air Force said in a statement.
The statement said Heather Wilson, the Air Force secretary, and Gen. David Goldfein, the Air Force chief of staff, had ordered the Air Force inspector general to “conduct a complete review of the Kelley case.”
The Air Force also said it was considering whether other convictions had been improperly left unreported to the federal database for firearms background checks.
New details of the killings also emerged on Monday, including a possible motive. Law enforcement officials said Mr. Kelley may have been driven by anger toward his estranged wife’s family, the final chapter in a life full of domestic rage. In addition to his court-martial, in which his previous wife was the victim, he had been investigated on a rape complaint, though he was not charged and his relationship with the woman in the complaint was unclear.
The mother of Mr. Kelley’s most recent wife, Danielle, was a member of the First Baptist Church here, the target of Mr. Kelley’s rage on Sunday.
“The suspect’s mother-in-law attended this church,” Freeman Martin, a spokesman for the Texas Department of Public Safety, said at a news conference on Monday. “We know that he had made threatening texts,” he added.
“This was not racially motivated. It wasn’t over religious beliefs. It was a domestic situation going on,” Mr. Martin added. Mr. Kelley’s wife and her parents were not at the church on Sunday, the authorities said. They could not be reached for interviews on Monday.
Among the victims of the massacre, the worst mass shooting in Texas history were eight members of one family and at least a dozen children, one as young as 18 months old, officials said. One of the victims was pregnant, and officials included the child she was carrying in the death toll of 26.
Mr. Kelley, who was dressed in all black and wore a skull-face mask, emerged from the church after he was done the shooting, then was met by gunfire from a bystander outside, who hit Mr. Kelley in the leg and the torso. Mr. Kelley made it back to his car and led the bystander and another man on a dramatic chase that ended in a crash, with Mr. Kelley dead behind the wheel. He had shot himself in the head, officials said.
“I think that mental health is your problem here,” Mr. Trump said at a joint news conference with Prime Minister Shinzo Abe of Japan. “This was a very, based on preliminary reports, very deranged individual.”
On Tuesday, Mr. Trump was asked during a news conference in South Korea whether he would support “extreme vetting” of gun buyers, comparable to the vetting his administration has sought to impose on visitors from some predominantly Muslim countries.
“If you did what you’re suggesting, there would have been no difference three days ago,” the president replied, “and you might not have had that very brave person who happened to have a gun or a rifle in his truck go out and shoot him and hit him and neutralize him.”
“If he didn’t have a gun, instead of having 26 dead, you would have had hundreds deader,” Mr. Trump said, reiterating an argument he has made after previous mass shootings — that more guns, not less, could be the answer.