Updated at 12:45 p.m. Thursday with additional information about the shooting.

A concealed carry holder is being heralded as a hero by Arlington police for preventing mass murder by killing an "incoherent" gunman at a sports bar Wednesday evening.

Before he was shot about 6:15 p.m., the gunman killed the manager of Zona Caliente in the 6500 block of South Cooper Street, police spokesman Christopher Cook said.

Police later identified the gunman as 48-year-old James Jones of Grand Prairie and the victim as 37-year-old Cesar Perez of Duncanville. The man who killed Jones has not been identified.

Authorities later found two loaded guns and two knives on Jones, Cook said Thursday.

"We do believe he had the capacity to do much greater harm," Cook said.

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When Jones entered the business, some witnesses told police, he started yelling incoherently while standing at the bar.

"People didn't know who he was yelling at," Cook said.

Zona Caliente in south Arlington (Tom Fox / The Dallas Morning News)

Perez was trying to talk to Jones when he was fatally shot. Police do not believe they knew each other.

That's when a customer fired his gun at Jones.

"After he was struck once, the suspect started shooting at the front door," Cook told the Arlington Voice. "We know people were trying to escape, but we're not sure if he was just trying to harm others."

More than a dozen customers and a handful of employees were in the sports bar at the time of the shooting.

Cook said the customer, who was dining with his wife, "prevented further loss of life."

The customer was carrying a handgun under the Texas concealed handgun license program, Cook later confirmed.

"We're treating the good guy as sort of a hero," he said.

1 / 4Arlington police investigate a shooting in which two people were found dead at the Zona Caliente Sports Bar and Grill on South Cooper Street in Arlington. (Tom Fox / Staff Photographer) 2 / 4Zona Caliente Sports Bar employees wait outside the restaurant as Arlington police investigate a shooting in which two people were shot dead inside on S. Cooper St. in Arlington, Wednesday, May 3, 2017. The shooting suspect walked to the end of the bar and shot an employee he was talking to. Seeing this happen, a diner got up and shot the suspect dead. There were 15-20 people at the bar n a handful of employees in the restaurant. (Tom Fox / Staff Photographer) 3 / 4Arlington police investigate a shooting in which two people were shot and killed at the Zona Caliente Sports Bar and Grill on S. Cooper St. in Arlington, Wednesday, May 3, 2017. The shooting suspect walked to the end of the bar and shot an employee he was talking to. Seeing this happen, a diner got up and shot the suspect dead.(Tom Fox / Staff Photographer) 4 / 4A woman who was gathered with employees visits with Arlington police who were investigating the shooting in which two people were killed at the Zona Caliente Sports Bar and Grill on S. Cooper St. in Arlington, Wednesday, May 3, 2017. (Tom Fox / Staff Photographer)

One other person was hurt, though it wasn't clear if it was a restaurant customer or employee. Police said that person was injured by glass while trying to get out.

Friends took to social media to honor Perez.

More than 100 people reacted to a post on his personal profile that his sister wrote.

Breaking News Producer Claire Cardona contributed to this report.