"Without the actions of Dr. Cheng, it is no doubt that there would be numerous additional victims in this crime," officials said.
ALISO VIEJO, Calif. (KABC) -- A prominent Orange County doctor who was killed during a mass shooting at a Laguna Woods church on Sunday is being hailed as a hero after he tackled the gunman and attempted to disarm him, which allowed parishioners to step in and help.
During a press conference led by the Orange County Sheriff's Department on Monday, Sheriff Donald Barnes said John Cheng, a doctor who specialized in sports medicine, immediately went after the suspect as the shooting inside the Geneva Presbyterian Church on El Toro Road began to unfold.
"Without the actions of Dr. Cheng, it is no doubt that there would be numerous additional victims in this crime," said Barnes.
Barnes said according to witnesses, Cheng went straight for the suspect - who was identified as 68-year-old David Chou of Las Vegas - and took him down.
A group of congregants stepped in to help Cheng, using items inside the church to stop Chou, who was ultimately hogtied by the legs with an extension cord.
During the struggle, Cheng was shot several times. He was pronounced dead at the scene.
"The heroic actions of Dr. Cheng ... literally the meaning of good versus evil between Dr. Cheng and the suspect in this case," said Barnes.
Cheng, who was 52 years old, leaves behind his wife and two children.
"After others had been shot, he took it upon himself to charge across the room and to do everything he could to disable the assailant," said Orange County District Attorney Todd Spitzer. "He was shot, and then there was an attempt to shoot him again, but the gun jammed, and he succumbed to his injuries."
Spitzer continued, saying Cheng "sacrificed himself so that others could live."
"That irony in a church is not lost on me," he said.
WATCH | OC DA Todd Spitzer praises Dr. John Cheng's heroic efforts to stop Laguna Woods church shooter
Cheng help co-found South Coast Medical Group, which is about four miles from where Sunday's deadly shooting occurred. There is a growing memorial from his patients and colleagues right outside the family practice.
"I have no doubt that everybody that was in there would not be with us today had it not been for Dr. John Cheng being there yesterday," said South Coast Medical Group Executive Director Johanna Gherardini.
Cheng's work family says the heroic doctor was not part of Geneva Presbyterian Church, but rather, he had taken his mother there for the first time Sunday since his father passed away a month ago. Gherardini says his family is heartbroken and in shock.
"They're devastated," she said. "He was their man."
Gherardini also said Dr. Cheng was a master of martial arts and taught everyone how to protect themselves in an emergency.
"He was adamant that everybody should know how to defend themselves," Gherardini said. "I one hundred percent know exactly. When they had said that he gone across the room and charged him. I can see him doing that."
His colleagues said they always knew Dr. Cheng had a passion for medicine and healing, and now he's hailed a hero for paying the ultimate sacrifice to save others.
"He was a protector and that's exactly what he did," Gherardini said.
Cheng's colleagues say they plan to host a memorial in the doctor's honor in the near future.
WATCH | Sheriff Barnes describes Dr. Cheng's heroism
Meanwhile, Chou was booked on one felony count of murder and five felony counts of attempted murder. He is being held on $1 million bail.
The Orange County District Attorney's office is expected to officially charge him on Monday.
Officials said the shooting was a "politically-motivated hate incident" and is now being investigated as a hate crime. Barnes said Chou, a U.S. citizen from Taiwan, was motivated by anger over political tensions between China and Taiwan.
That anger pushed him to travel to Southern California from Las Vegas, where he lives alone and worked in security.