FORT WORTH (Texas) • Alarms went off in Mr Jack Wilson's head the moment a man wearing a fake beard, a wig, a hat and a long coat walked into a Texas church for Sunday services.
By the time the man approached a communion server and pulled out a shotgun, Mr Wilson and another security volunteer were already reaching for their own guns.
The attacker shot the other volunteer, Mr Richard White, and then the server, Mr Anton "Tony" Wallace, sending congregants scrambling for cover.
The gunman was heading towards the front of the sanctuary as Mr Wilson searched for a clear line of fire. "I didn't have a clear window," he said, referring to church members who "were jumping, going chaotic".
Mr Wilson, a 71-year-old firearms instructor who has also been a reserve sheriff's deputy, said: "They were standing up. I had to wait about half a second, or a second, to get my shot. I fired one round. The subject went down."
That single shot ended the attack that killed Mr Wallace, 64, and Mr White, 67, at the West Freeway Church of Christ in the Fort Worth-area town of White Settlement.
Mr Wilson said the entire confrontation was over in no more than six seconds. More than 240 congregants were in the church at the time.
As Mr Wilson approached the fallen attacker, he noticed five or six other members of the volunteer security team he had trained with their guns drawn. He said they had had their eyes on the man since he arrived. During the service, Mr White and Mr Wilson had stationed themselves at the back of the church, watching him.
The Texas Department of Public Safety on Monday named the attacker as Keith Thomas Kinnunen, 43. His motive is being probed.
Speaking to reporters outside the church on Monday, Texas Attorney-General Ken Paxton said the authorities "can't prevent mental illness from occurring, and we can't prevent every crazy person from pulling a gun. But we can be prepared like this church was".
Mr Wilson described Kinnunen's gun as a short-barrelled 12-gauge shotgun with a pistol grip. Shotguns with barrels less than 18 inches (46cm) long are restricted under federal law and can be legally owned in Texas only if they are registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives.
After the attack, Texas officials hailed the state's gun laws, including a measure enacted last year that affirmed the right of licensed handgun holders to carry a weapon in places of worship, unless the facility bans them.
That law was passed in the aftermath of the deadliest mass shooting in Texas history, which was also at a church. In the 2017 massacre at First Baptist Church of Sutherland Springs, a man who opened fire on a Sunday morning congregation killed more than two dozen people. He later killed himself.
President Donald Trump tweeted his appreciation for the state's gun legislation on Monday night, saying: "Lives were saved by these heroes, and Texas laws allowing them to carry arms!"
Investigators have searched Kinnunen's home in nearby River Oaks. Kinnunen appeared to have more serious brushes in other jurisdictions. He was arrested in 2009 on charges of aggravated assault with a deadly weapon in Fort Worth and in 2013 for theft, according to Tarrant County court records.
Mr Wilson said the church started the security team about 18 months ago after moving to a new building and becoming concerned about crime in the area. Mr Wilson has been a firearms instructor since 1995, spent six years in the Army National Guard and was a Hood County reserve deputy.
"I don't feel like I killed a human, I killed an evil," Mr Wilson said. "That's how I'm coping with the situation."