The big question: Why?

A video that spread on social media showed a gunman exiting his vehicle and opening fire outside H&M about 3:37 p.m. Saturday. 

The assailant, wearing tactical gear, was armed with an AR-15-style rifle, according to a statement by President Joe Biden. In all, the shooter had three firearms on him and five in his vehicle, all legally purchased, authorities said.

Freddie, Spainhouer’s son, said he heard “muffled pops” while on a break at H&M. 

“At first I thought it was like a shelf that tumbled over,” he told the Chronicle. “And then there were multiple pops.”

When he and a co-worker realized the pops were gunfire, they helped usher other employees and shoppers — including a woman who had been shot — into a stockroom. 

“We started moving totes and boxes and whatever we could find to barricade the doors,” Freddie said.

Meanwhile, a police officer on an unrelated call heard the shots and killed the assailant, identified as Mauricio Garcia, 33. 

The officer, whose name has not been released, “distinguished himself in an exemplary manner when he immediately addressed an attacker who was injuring and murdering innocent victims,” Allen Police Chief Brian Harvey said.

Those who died were Cho Kyu Song, 37; Kang Shin Young, 35; James Cho, 3; Daniela Mendoza, 11; Sofia Mendoza, 8; Christian LaCour, 20; Elio Cumana-Rivas, 32; and Aishwarya Thatikonda, 26.

The killer was kicked out of the Army during basic training in 2008, said Hank Sibley, the Texas Department of Public Safety’s North Texas regional director. Mental health issues were the reason for his dismissal, according to The Associated Press.

“The big question we’re dealing with right now is: What’s his motive? Why did he do this?” Sibley said. “We do know that he had neo-Nazi ideation. He had patches. He had tattoos.”

But the DPS official said, “To me, it looks like he targeted people based on the location rather than a specific group of people. He was very random in the people he killed. It didn’t matter the age, race or sex. He just shot people, which is horrific in itself.”

Spainhouer said he does not consider himself a hero.

Rather, he describes his son as a hero.

“He saved lives,” the father said on Twitter. “I’m very proud of him.”

In another tweet, he identified the heroes as “the 911 operators, the store employees who took immediate actions to save lives of shoppers, the police officer who took out the shooter & those who responded to assist in trying to save lives.”

Later, he wrote: “I only saw suffering and tried to stop it, saw despair and tried to comfort, hopelessness and tried to give hope. Anyone can do that. Everyone should.”