(CNN) The carnage started even before the gunman entered the church.
It was a gorgeous day in Sutherland Springs, and worshipers at First Baptist Church were singing the praises of Christ. Suddenly, the joyous prayers were drowned out by screams of terror.
"Out of nowhere, shots started coming through the windows," said David Brown, whose mother was sitting in the back pew. "Windows broke out. Shots were flying."
The gunman started unloading his 450 rounds of ammo from outside, targeting the congregation of about 50 people.
Then came the killer -- dressed in tactical gear and armed with an assault rifle as he stormed in through the front door of the small Texas church.
Video from inside the church showed that the gunfire lasted about seven minutes, said an official briefed on the case, according to The New York Times.
Roseanne Solis was sitting near the entrance. She told CNN that the gunman, Devin Patrick Kelley, "was looking all around and shooting at everybody -- going through the rows, just shooting at everybody."
"I didn't even want to move. I know that was going to be my last day to live," she said.
Solis dropped to the ground but was struck in the left arm, she told CNN affiliate KSAT. "I could feel the gunshots. I saw them on the carpet," she said.
Brown said his mother recalled the gunman walking up and down the aisles several times.
"She stayed on the ground the whole time -- never saw him, just saw his boots as he walked around the church," Brown said.
At one point, the shooting stopped. From the ground, Solis saw a man's feet walk by and thought maybe the police had arrived.
But it was the killer, walking pew by pew, looking for more survivors to shoot.
"Everybody was saying, 'Be quiet! it's him, it's him!'" Solis told the affiliate.
Not everyone could keep quiet. Young children in the church couldn't stop crying, said Solis' husband, Joaquin Ramirez. So Kelley found the children and shot them point-blank.
As the massacre continued, Ramirez made eye contact with Annabelle Pomeroy -- the 14-year-old daughter of the church's pastor. She was crying for help, Ramirez told KSAT.
Realizing Annabelle might get shot, Ramirez motioned with his finger for her to stay quiet. It didn't work. Annabelle was killed.
The gunman eventually made his way to the back pew, where Brown's mother was hiding, "and started shooting the lady next to her multiple times," Brown said.
Brown's mother was certain she would be next, "and her life was about to end."
"Then somebody with a gun showed up at the front of the church (and) caught the shooter's attention," Brown said. "And he left, and that was the end of the ordeal."
The Wilson County Sheriff's Office arrived four minutes after the first 911 call, the Texas Department of Public Safety said.
By the end of the massacre, 26 people were dead including an unborn child, authorities said. The fatalities included eight members of the same family and Kelley's own grandmother-in-law.
Ramirez and Solis survived by playing dead.