The United States Air Force missed six opportunities to alert law enforcement authorities about an airman’s history of domestic abuse that would have stopped him from legally buying firearms that he used to kill 26 people in a Texas church in 2017, according to a government report released this week.

The 131-page report, by the inspector general’s office of the Department of Defense, found that the airman, Devin P. Kelley, had been convicted of domestic violence by an Air Force general court-martial but that his fingerprints and the final disposition of the case were never forwarded to the F.B.I. as policies required.

Those oversights allowed him to pass mandated background checks and to buy four firearms from a federally licensed firearms dealer. Mr. Kelley used three of those weapons when he opened fire on the First Baptist Church in Sutherland Springs, Tex., on Nov. 5, 2017, according to the report, which was dated Thursday. The shooting left 26 people dead and 22 others wounded.

Mr. Kelley, 26, was dressed all in black and wearing a skull-face mask when an armed bystander outside of the church fired at him. Mr. Kelley, who was struck in the leg and torso, made it back to his car and led the bystander and another man in a chase that ended in a crash, with Mr. Kelley dead behind the wheel. He had shot himself in the head, officials said.