SUTHERLAND SPRINGS, Texas — The gunman who killed 26 people at a small-town Texas church had a history of domestic violence and sent threatening text messages to his mother-in-law, a member of First Baptist, before the attack in which he fired at least 450 rounds at helpless worshippers, authorities said Monday.

A day after the deadliest mass shooting in state history, the military acknowledged that it did not submit the shooter’s criminal history to the FBI, as required by the Pentagon. If his past offenses had been properly shared, they would have prevented him from buying a gun.

Investigators also revealed that sheriff’s deputies had responded to a domestic violence call in 2014 at Devin Patrick Kelley’s home involving a girlfriend who became his second wife. Later that year, he was formally ousted from the Air Force for a 2012 assault on his ex-wife in which he choked her and struck her son hard enough to fracture his skull.

In the tiny town of Sutherland Springs, population 400, grieving townspeople were reeling from their losses. The dead ranged from 18 months to 77 years old and included multiple members of some families.

“Our church was not comprised of members or parishioners. We were a very close family,” said Sherri Pomeroy, the wife of the church pastor, who was out of town with her husband when the attack happened. “Now most of our church family is gone.”

The couple’s 14-year-old daughter, Annabelle Pomeroy, was among those killed.

Kelley’s mother-in-law sometimes attended services there, but the sheriff said she was not at church on Sunday.

The massacre appeared to stem from a domestic situation and was not racially or religiously motivated, Texas Department of Public Safety Regional Director Freeman Martin said. He did not elaborate.

Based on evidence at the scene, investigators believe Kelley died of a self-inflicted gunshot wound after he was chased by bystanders, one of whom was armed, and crashed his car.

Kelley, 26, also used his cell phone to tell his father he had been shot and did not think he would survive, authorities said.

While in the military, Kelley served in logistics readiness at Holloman Air Force Base in New Mexico from 2010 until his 2014 discharge, Air Force spokeswoman Ann Stefanek said.

He was discharged for the assault involving his previous wife and her child and had served a year of confinement after a court-martial.