By JIM VERTUNO

Associated Press

SUTHERLAND SPRINGS, Texas (AP) — A gunman dressed in black tactical-style gear and armed with an assault rifle opened fire inside a small South Texas church, killing 26 people in an attack that claimed tight-knit neighbors and multiple family members ranging in age from 5 to 72 years old.

Once the shooting started Sunday at the First Baptist Church in Sutherland Springs, there was likely "no way" for congregants to escape, said Wilson County Sheriff Joe D. Tackitt Jr. Officials said about 20 others were wounded.

"He just walked down the center aisle, turned around and my understanding was shooting on his way back out," said Tackitt, who said the gunman also carried a handgun but that he didn't know if it was fired. Tackitt described the scene as "terrible."

"It's unbelievable to see children, men and women, laying there. Defenseless people," he said.

Tackitt told CNN on Monday morning that the gunman's former in-laws attended services at the church "from time to time" but weren't in attendance Sunday.

Authorities didn't identify the attacker during a news conference Sunday night. But two other officials — one a U.S. official and one in law enforcement — identified him as Devin Kelley. They spoke to The Associated Press on the condition of anonymity because they weren't authorized to discuss the investigation.