Saturday night’s massacre at a dance hall in Monterey Park, entered and pointed a semi-automatic pistol at him.
Related: Monterey Park shooting suspect, 72, found dead of self-inflicted gunshot
“He was looking at me and looking around, not hiding that he was trying to do harm,” Tsay, 26, told the New York Times. “His eyes were menacing.
“How [the weapon] was built and customized, I knew it wasn’t for robbing money. From his body language, his facial expression, his eyes, he was looking for people.”
Tsay was unaware that the man had arrived straight from the Star Dance Studio in Monterey Park, another majority Asian community of southern California, where he opened fire on patrons at an event celebrating lunar new year. Five men and five women were killed there, and at least 10 others were wounded, authorities said.
Police later found the 72-year-old killer dead from an apparent self-inflicted gunshot wound in a van in Torrance, about 30 miles away.
Tsay said he was in a lobby office of his family’s studio, watching the ballroom, which only had three people still dancing as the studio’s own New Year event wound down, when he heard the entrance door swinging behind him.
He said he heard a clang that sounded like two metallic objects hitting each other, turned to see the man with his gun raised, and knew he had to act.
“My heart sank,” he told the Times. “I knew I was going to die.”
In an interview with ABC’s Good Morning America on Monday, Tsay, a coder, described how the pair fought for about a minute and a half before he was able to wrest away the gun.
“I lunged at him with both my hands, grabbed the weapon, and had a struggle,” he said.
He continued: “We struggled into the lobby, trying to get the gun away from each other. He was hitting me across the face, bashing me in the back of my head, I was trying to use my elbows to get the gun away from him.
“Finally, at one point I was able to pull the gun away from him, shove him aside, create some distance, point the gun at him, intimidate him, shouting, ‘Get the hell out here. I’ll shoot. Get away. Go.’”
Tsay said the man lingered for a moment or two, then turned and left. At that point, Tsay said, he called the police while still holding the gun.
“I was shaking all night – I couldn’t believe what happened,” he said, adding that he has bruising on his body, his face and the back of his head.
At a press conference late Sunday, with information still scant, Los Angeles county sheriff Robert Luna said he believed there had been two citizens who confronted the shooter at Lai Lai. But Tsay’s account and security footage appeared to show it was only him.
“It was just my son. He could have died,” Brandon’s father, Tom Tsay, told the New York Times. “He’s lucky – someone was watching over him.”
Luna had no doubt the confrontation prevented greater bloodshed at the hands of an attacker whose motivation remained under investigation late Sunday.
“They saved lives,” the sheriff said. “This could’ve been much worse.
“The weapon that we recovered at that second scene I am describing as a magazine-fed semiautomatic assault pistol – not an assault rifle, but an assault pistol that had an extended large capacity magazine attached to it.”
Tsay told the Times he was heartbroken for the community in which his family had opened the studio, named Lai Lai by his grandmother, or “come, come” in Chinese, three decades earlier.
“We have such a tight-knit community of dancers,” he said. “It feels so terrible something like this happened, to have one of our individuals try to harm others.”
Sunday’s killings in Monterey Park came during the 36th mass shooting in the US so far this year, according to the Gun Violence Archive. The archive considers shootings in which at least four people are wounded or killed – not counting any attackers – to be mass shootings.