SUTHERLAND SPRINGS, Tex. — As Lorenzo Flores Jr. pulled into the Valero gas station on Sunday morning, he caught sight of an armed man in black stalking the First Baptist Church across the highway — and knew in his gut that tragedy was descending on this blink-and-you-miss-it town of trailer homes and rusting pumpjacks.

“He was dressed G.I. Joe-style, not like us normal guys around here who have a rifle for dove hunting,” said Mr. Flores, 56, who runs Theresa’s Kitchen, a food stand inside the Valero station that sells burritos and tacos. “Then I saw him hitting the church with bullets from the outside. It was just bam-bam-bam, the sound when a dude keeps his finger on the trigger.”

By the time the shooting stopped, at least 26 people at the First Baptist Church would be dead or dying.

Tears welled in Mr. Flores’s eyes as he spoke on Monday about customers, friends and neighbors who were now gone, like Joann Ward, a day care provider who grew up here with his son. He looked at the ground as he recalled how Ms. Ward would always order her favorite burrito, asking him, “Where’s my chorizo and egg?”