JOHNNIE Langendorff was driving in his truck near the Sutherland Springs First Baptist Church on Sunday morning when he saw two men shooting at each other: the suspect in the massacre and a member of the public.

“I pulled up to the intersection where the shooting happened.

“I saw two men exchanging gunfire, the other being the citizen of the community. The shooter of the church had taken off, fled in his vehicle, the other gentleman came and said we need to pursue him. And that’s what I did, I just acted,” Mr Langendorff told a local TV station.

Wilson County Sheriff Joe Tackitt Jnr said services were under way Sunday at First Baptist Church of Sutherland Springs when the gunman, Devin Kelley, 26, dressed in black tactical gear, walked down the centre aisle and began “shooting on his way back out”.

Kelley killed at least 26 people – including several children – and wounded at least 10, law enforcement officials said.

The victims ranged in age from five to 72 years old.

Freeman Martin, Texas Department of Public Safety regional director, said an armed resident engaged the suspect, who fled in his vehicle.

Mr Langendorff appeared on camera with a small beard, cowboy hat and chewing a toothpick. He has a tattoo of a bull’s skull across his neck.

“He was just a member of the community and he came to my vehicle in distress with his weapon,” Mr Langendorff said of the member of the public, who was not named, who asked him to give chase to the alleged killer.

“He explained very quickly what happened. He got into the truck and I knew that it was time to go.”

The duo soon caught up with the suspect, Mr Langendorff said.

“He got a little bit of a jump on us. We were doing about 95mph down Route 539 going around traffic and everything. Eventually he came to a kind of a slowdown and after that we got within just a few feet of him and then he got off the road,” he said.

“He just lost control. That is when I put the vehicle in park and I was still on the phone to dispatch (police). The other gentleman jumped out and has his rifle drawn on him. He didn’t move after that,” he added.

“We led police to him. Everybody else was headed to the church, all the other officers were responding to the church. From the time we actually stopped, it was about five to seven minutes. The police arrived and then they pushed us back and they took care of the rest. I didn’t see anything after that.” Freeman Martin, the regional director for the Texas Department of Public Safety, said it appeared that Kelley died from a self-inflicted gunshot wound after first being shot by a “good Samaritan”.

Authorities did not immediately identify a motive for the attack. Kelley served briefly in the Air Force but received a court martial in 2012, a military spokeswoman said.

Three mass shootings have rocked the US in the past 17 months – and they have been some of the nation’s bloodiest.

Before the shooting at the First Baptist Church in Sutherland Springs, about 35 miles from San Antonio, just a little over a month ago in Las Vegas the country’s worst massacre in recent years came when Stephen Paddock gunned down 58 people at an outdoor country music festival from his hotel room.

And less than a year and a half ago, Omar Mateen, a 29-year-old security guard, killed 49 people and wounded 58 others at a gay nightclub in Orlando that was hosting a Latin night on June 12, 2016. Mateen was killed by police. The shooting had been the deadliest terror attack in the US since 9/11.