By Jon Herskovitz and Lisa Maria Garcia
SUTHERLAND SPRINGS, Texas (Reuters) - A man court-martialed by the U.S. Air Force on charges of assaulting his then-wife and child had sent threatening messages to his mother-in-law who sometimes attended the rural Texas church where he fatally shot 26 people, officials said on Monday.
Suspected gunman Devin Patrick Kelley injured another 20 people when he opened fire in the white-steepled First Baptist Church in Sutherland Springs on Sunday. The attack ranks among the five deadliest mass shootings carried out by a single gunman in U.S. history.
As he left the church, Kelley, 26 was confronted by a man identified by media as Stephen Willeford, who was armed with an assault rifle who shot and wounded Kelley, authorities said.
As Kelley fled in a Ford Expedition, Willeford waved down a passing motorist and they chased the suspect at high speeds.
"This good Samaritan, our Texas hero, flagged down a young man from Seguin, Texas, and they jumped in their vehicle and pursued the suspect," said Freeman Martin, a spokesman for the Texas Department of Public Safety.
Kelley called his father during the chase to say he had been shot and might not survive, officials said. He later crashed his vehicle, shot himself and died, they added. An autopsy will determine if he died from the self-inflicted wound or after being shot in the gunfight, officials said.
Kelley was involved in a domestic dispute with the family of Danielle Shields, a woman he married in 2014, and the situation had flared up, according to officials and official records. It was unclear if the two were still married.
"There was a domestic situation going on within the family and the in-laws," Martin told reporters outside the church on Monday morning. "The mother-in-law attended the church ... she had received threatening text messages from him."
Wilson County Sheriff Joe Tackitt said in an interview that the family members were not in the church during Kelley's attack.
"I heard that (the in-laws) attended church from time to time," Tackitt said. "Not on a regular basis."
The attack came about a month after a gunman killed 58 people in Las Vegas in the deadliest shooting by a lone assailant in U.S. history.
The Texas death toll matched the fatalities at the Sandy Hook Elementary School in Newtown, Connecticut, where a man shot and killed 26 children and educators after slaying his mother at their home in December 2012.
The dead ranged in age from 18 months to 77 years.
Ten of the wounded in Texas remained in critical condition on Monday morning, officials said.
Wearing a black bullet-proof vest and skull mask, Kelley used a Ruger AR-556 semi-automatic rifle in the attack, authorities said. They recovered two other weapons, including at least one handgun, from his vehicle.
In rural Texas and in other states, gun ownership is a part of life and Republican leaders for years have balked at gun control, arguing that responsible gun owners can help deter crime.
Republican Texas Governor Greg Abbott told CBS News there was evidence that Kelley had mental health problems and had been denied a state gun permit.
"It's clear this is a person who had violent tendencies, who had some challenges," Abbott said.
Abbott and other Republican politicians said the mass shooting did not influence their support of gun ownership by U.S. citizens - the right to bear arms protected under the Second Amendment of the U.S. Constitution.
"This isn't a guns situation. I mean we could go into it but it's a little bit soon to go into it," U.S. President Donald Trump told reporters while on a trip to Asia. "Fortunately somebody else had a gun that was shooting in the opposite direction, otherwise ... it would have been much worse,"
Democrats renewed their call to restrict gun ownership.
"How many more people must die at churches or concerts or schools before we stop letting the @NRA control this country's gun policies," Democratic U.S. Senator Elizabeth Warren said on Twitter.
Kelley served at Holloman Air Force Base in New Mexico from 2010 until his discharge in 2014, according to the U.S. Air Force.
He was court-martialed in 2012 on charges of assaulting his wife and child, and given a bad-conduct discharge, confinement for 12 months and a reduction in rank, Air Force spokeswoman Ann Stefanek said.
The attack stunned Sutherland Springs, population about 400. John Stiles, a 76-year-old retired U.S. Navy veteran, said he heard the shots from his home about 150 yards (137 m) from the church.
"The wind was blowing and there was a bang, bang, bang," Stiles said. "My wife and I were looking for a peaceful and quiet place when we moved here but now that hasn't worked out."
(Additional reporting by Jane Ross in Sutherland Springs, Texas, Bernie Woodall in Fort Lauderdale, Florida and Peter Szekely in New York; Writing by Scott Malone; Editing by Mark Heinrich and Jeffrey Benkoe)