Law enforcement and witnesses say had it not been for the heroism of church members and leaders, many more could have been injured or killed.
Pastor Billy Chang and his wife describe their firsthand accounts of how they both rushed over to help when a gunman entered Geneva Presbyterian Church in Orange County and after barricading the doors, opened fire.
In an interview with NBCLA, Pastor Chang said he didn't feel fear, and even at 68 years old, he felt he had the strength to fight the suspect.
His wife, Yu Ling Chang, said she was scared, but in the moment, she knew what she had to do. Police believe the two saved dozens more from harm by taking action, fear or not.
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As the two gathered Monday night at the Christ Our Redeemer Church in Irvine, Pastor Chang said he could not help but feel guilt. The other hero of the tragedy, Dr. John Cheng, was killed.
"For [the] Cheng family because Dr. Cheng and his mother come to the church for me," he said.
In compelling images released Monday, Pastor Chang can be seen holding down the man with the gun seconds after the Changs thought to grab a chair to throw at him, possibly dislodging the gun from the suspect's hand.
Dr. Cheng charged the suspect, allowing others, like Pastor Chang and his wife, to step in and disarm the shooter.
Dr. Cheng died of his injuries.
Pastor Chang said even in the heat of the moment, the suspect said he couldn't breathe in Mandarin as parishioners held him down.
"He said in Mandarin, 'I cannot breathe,'" Pastor Chang said. "I tell the members let him a little loose, let him breathe."
In another image from moments after the shooting that left five others hurt, Yu Ling Chang can be seen grabbing an orange electrical cord to tie the suspect's legs down as her husband, Pastor Chang, holds him down.
"The gun is boom boom boom. Five people...hurting," she said, recounting the horror.
"Ten minutes police come here. 'Where the gun? Where the gun?'" she said.
Yu Ling said when the gun dropped to the floor, she grabbed it, and threw it in fridge.
She explains all she was trying to do is get the gun away from him.
All this was happening as Dr. Cheng laid next to them bleeding. Yu Ling can still hear Dr. Cheng's mother's cries.
"His mother cried, 'my son, my son, my son!" she said.
The Changs say COVID-19 kept them in Taiwan for a very long time, and this past week was their first chance to come back to Orange County to see everyone.
They thought Sunday would be a chance for a happy reunion.
Officials allege the gunman, 68-year-old David Wenwei Chou, drove from his home in Las Vegas to Geneva Presbyterian Church in Orange County, with the plan to kill all of the members of the congregation.
The shooting was a "politically motivated hate incident," OC Sheriff Don Barnes said at a news conference on Monday. "It is believed the suspect was upset about political tensions between China and Taiwan."
The church is a Taiwanese congregation.