THE gunman who opened fire in a small Texas church, killing 26 people, sent threatening text messages to his mother-in-law before the attack and had been confronted about domestic violence at least twice in the last five years, authorities said.
The deadliest mass shooting in state history claimed multiple members of some families, with the dead ranging in age from 18 months to 77 years, and tore gaping holes in a town with a population of just 400 people.
The massacre appeared to stem from a domestic situation and was not religiously motivated, said Texas Department of Public Safety Regional Director Freeman Martin.
Based on evidence at the scene, investigators believe Devin Patrick Kelley died of a self-inflicted gunshot wound after he was chased by armed bystanders and crashed his car.
The 26-year-old gunman also used his mobile phone to tell his father that he had been shot and did not think he would survive, authorities said.
The investigation showed that Kelley had displayed a pattern of violence spanning years.
In 2014, sheriff's deputies went to his home to investigate a domestic violence complaint involving him and his then-girlfriend. People in the house said there was no problem, and no arrests were made. Kelley married the girlfriend two months later.
That same year, Kelley was discharged from the Air Force for assaulting his wife and child and had served 12 months' confinement after a 2012 court-martial.
He had also been charged with misdemeanour animal cruelty in 2014 in Colorado and had been the focus of a protective order issued in that state in 2015.
The gunman's family relationships at the First Baptist Church in Sutherland Springs were uncertain.
The sheriff said Kelley's former in-laws sometimes attended services at the church but were not there on Sunday.
Mr Martin said the text messages were sent to the gunman's mother-in-law, who attended the church.
Once the shooting started, there was probably "no way" for congregants to escape, Wilson County Sheriff Joe D Tackitt Jr said.
The gunman, dressed in black tactical gear, fired an assault rifle as he walked down the centre aisle during worship services. He turned around and continued shooting on his way out of the building, Mr Tackitt said.
About 20 other people were wounded, 10 of whom were still in hospital in a critical condition.
Authorities said Kelley lived in New Braunfels, about 35 miles north of the church.
Investigators were looking at social media posts Kelley made in the days before the attack, including one that appeared to show an AR-15 semi-automatic weapon.
Kelley, who had a licence to serve as an unarmed private security guard, did not have a licence to carry a concealed handgun, Mr Martin said.
In the Air Force, 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.
On Sunday, the attacker pulled into a gas station across from the church, about 30 miles (48.28 km) south east of San Antonio, at around 11.20am on Sunday.
He crossed the street and started firing the rifle at the church, then continued firing after entering the white wood-frame building, Mr Martin said.
As he left, Kelley was confronted by an armed resident who "grabbed his rifle and engaged that suspect," Mr Martin said. A short time later, the suspect was found dead in his vehicle at the county line.
Twenty-three of the dead were found in the church. Two were found outside and one died after being taken to a hospital, Mr Martin said.
The man who confronted Kelley had help from another local resident, Johnnie Langendorff, who told KSAT-TV that he was driving past the church as the shooting happened.
He did not identify the armed resident but said the man exchanged gunfire with the gunman, then asked to get in Mr Langendorff's truck, and the pair followed as the gunman drove away.
He said the gunman eventually lost control of his vehicle and crashed. He said the other man walked up to the vehicle with his gun drawn and the suspect did not move.
"I was strictly just acting on what's the right thing to do," Mr Langendorff said.
Among those killed was the church pastor's 14-year-old daughter, Annabelle Pomeroy. Pastor Frank Pomeroy and his wife, Sherri, were both out of town when the attack occurred, Sherri Pomeroy wrote in a text message.
Church member Nick Uhlig (34), who was not at Sunday's service, told the AP that his cousin, who was eight months' pregnant, and her in-laws were among those killed. He later told the Houston Chronicle that three of his cousin's children also died.
Three guns were recovered. A Ruger AR-556 rifle was found at the church, and two handguns were recovered from the suspect's vehicle, according to the Bureau of Alcohol, Tobacco, Firearms and Explosives.