The veteran patrolmen who opened fire on the suit-clad gunman, Jeffrey Johnson, had only an instant to react when he whirled around and pointed a .45-caliber pistol at them as they approached him from behind on a busy sidewalk.
Officer Craig Matthews shot seven times, and Officer Robert Sinishtaj fired nine times, police said. Neither had ever fired their weapons before on a patrol.
The volley of gunfire felled Johnson in just a few seconds and left nine other people bleeding on the sidewalk.
In the initial chaos Friday, it wasn't clear whether Johnson or the officers were responsible for the trail of the wounded, but based on ballistic and other evidence, "it appears that all nine of the victims were struck either by fragments or by bullets fired by police," Police Commissioner Raymond Kelly told reporters Saturday at a community event in Harlem.
Police officials have said the officers appeared to have no choice but to shoot Johnson, whose body had 10 bullet wounds in the chest, arms and legs.
The officers confronted Johnson as he walked, casually, down the street after gunning down a former co-worker on the sidewalk outside the office they once shared. The shooting happened at 9 a.m., as the neighborhood bustled with people arriving for work.
The gunman and his victim, Steve Ercolino, had a history of workplace squabbles before Johnson was laid off from their company, Hazan Import Corp., a year ago. At one point, the two men had grappled physically in an elevator.
John Koch, the property manager at the office building where the men worked, said security camera footage showed the two pushing and shoving. The tussle ended when Ercolino, a much larger man, pinned Johnson against the wall of the elevator by the throat, Koch said. Ercolino let him go after a few moments, and the two men went their separate ways.
"They didn't like each other," Koch said.
After shooting Ercolino, Johnson, an eccentric T-shirt designer and avid bird-watcher who wore a suit every day, even when photographing hawks in Central Park, walked away as if nothing had happened.
Alerted by a construction worker, officers Matthews and Sinishtaj gave chase as Johnson rounded a corner and walked along Fifth Avenue in front of the landmark skyscraper.
A security videotape from the scene shows several civilians - including three sitting on a bench only a few feet away - scattering as the officers opened fire.
Police have determined that three people were struck by whole bullets - two of which were removed from victims at the hospital - and the rest were grazed "by fragments of some sort," Kelly said.
Two women with leg wounds and a man with a wound to his buttocks required surgery and remained hospitalized Saturday. They were listed in stable condition.
Both Matthews, 39, and Sinishtaj, 40, joined the nation's largest police department 15 years ago.
Matthews had drawn attention this year by suing the New York Police Department, accusing his superiors of unfairly punishing him for not meeting arrest quotas. A judge threw out the complaint.
The union representing the two officers didn't immediately respond to a message left seeking comment.
The shooting didn't deter tourists from flocking to the Empire State Building as usual on Saturday.
Patricia Flynn, 57, a retired schoolteacher, visited the building's peak with her elderly mother, who once worked in the skyscraper as a secretary.
"But I didn't tell her what happened," said Flynn, adding that her mother was unaware of Friday's shooting. "And she really enjoyed the view."
A group of 31 tourists from France held a meeting Friday night at their nearby hotel to decide whether to cancel their planned Empire State Building visit.
"We were scared, and we thought it was a risk," said Catherine Krukar, 38, a teacher.
But in the end, they went ahead with the visit, she said after descending from the observation tower,
"We know it can happen anywhere, and we wanted to see the Empire State Building," Krukar said. "It was beautiful!"
Contributing to this report from New York were David B. Caruso, Colleen Long and the AP News Research Center.