Police officers fired a total of 16 rounds; one officer shot nine while another one shot seven, the New York Police Department said.
The violence erupted just as visitors began to queue up to ascend the famous New York skyscraper in one of Manhattan's busiest neighborhoods.
Police identified the shooter as 58-year-old Jeffrey Johnson, who was apparently laid off from his job as a designer of women's accessories at Hazan Import last year.
"We have on tape the perpetrator pulled his gun out and tried to shoot at the cops," Mayor Michael Bloomberg said. "Whether he got off any bullets or not, to be determined."
Police Commissioner Ray Kelly said the bystanders were not hit directly by police, but rather the officers' struck "flowerpots and other objects around, so ... their bullets fragmented and, in essence, that's what caused the wounds."
Earlier Friday, Bloomberg told reporters that some of the wounded may have been inadvertently hit in the crossfire or by ricocheting bullets.
Six of the wounded were treated and released at hospitals as of Friday evening, while three others remained hospitalized, Kelly said.
One of those wounded, Erica Solar, was on her way to get a cup of coffee at Dunkin' Donuts when a bullet tore through the back of her leg, her brother said. The Manhattan receptionist is being treated at the city's Bellevue Hospital.
Robert Asika, a 23-year-old city tour guide, was on his way to work when he got caught in the crossfire.
"When I turned around, I saw a guy reach in his suit and he pulled out a gun," he told CNN affiliate WCBS. "I guess he shot at the police officer. And the police officer shot him. And one of them shot me in the arm, and I fell."
The slain victim was identified as Steven Ercolino by the president of State University of New York at Oneonta, where he was a 1992 graduate.
"We were saddened to learn that a member of our Oneonta alumni community was the victim of this tragic and senseless killing," Nancy Kleniewski said. "Our thoughts and prayers are with Steve's family."
Ercolino, 41, is listed as a vice president of sales at Hazan Import Corp., according to his LinkedIn profile.
"It's not something that should happen to a loving person like that," his brother Paul Ercolino told CNN on Friday night. "He's going to be so missed by everybody. He was a light of so many lives."
Johnson had a longstanding dispute with Ercolino "apparently centered on the fact that Ercolino was not selling -- at least in Johnson's opinion -- as much of his product ... as he wanted him to," according to Kelly.
The suspect lost his job last year "as a result of downsizing," but continued to return to the company regularly, having "a confrontation with Ercolino virtually every time he went back," said the police commissioner.
Both men filed harassment complaints against each other in April 2011, Kelly added.
On Friday, Johnson was wearing a business suit and carrying a briefcase as he waited for Ercolino outside his business on West 33rd Street. When Ercolino appeared, "Without any conversation, he shot him once in the head and then shot him in the torso," said the police commissioner.
Johnson then walked east, before eventually turning north. A construction worker was among those who dashed after the gunman after the initial gunshots. Eventually, they alerted two police officers in front of the Empire State Building that the suspect "just killed a man around the corner," Kelly said.
The police commissioner said the suspect pulled his gun out of his briefcase as the officers approached, pointing at them. The officers then fatally shot Johnson.
A brief surveillance video released Friday night by police show the man walking behind a large planter on a busy street. He appears to point something as two officers approach, coming to within a few feet of him. Then, as bystanders run off in all directions, the man falls abruptly to the ground after apparently being shot.
Another video shot by an Australian tourist offered a street-level glimpse of the shooting, which prompted road closures and frightened onlookers.
At least two police officers appear in the video with their guns drawn over a man who is lying on his back. The man appears to be alive, with his hands partly outstretched.
The camera then pans to others who are apparently injured, as pedestrians duck behind buildings on Manhattan's Fifth Avenue.
Witnesses said police shot Johnson at least three times.
"I heard the gunshots," said Anika Basu, who was on a bus near the building when the shooting happened. "I looked towards the left and saw three
"We didn't realize if it was an actual gunshot or what," she said.
"It's just a crazy scene here," added Rebecca Fox, who works across the street from the Empire State Building. She had been getting coffee and had her headphones on when she saw people running.
"When I walked across the street, I saw a woman who had been shot in the foot. And she was just in shock, sitting there," Fox said. "I looked down, I saw another man had been laying on the ground, and he wasn't moving."
One witness -- 22-year-old Max Kaplan -- said he heard at least nine shots and saw ambulances race to the scene.
"We're all very shaken up at the office," he said.
Aaron Herman, a CNN iReporter, painted a portrait of confusion.
"It was a little chaotic. Police had barricaded the area, and I saw one woman who was a victim. I think she had been grazed," he said. "Some said they heard around three 'pops' and ran into nearby local stores to be safe."
Authorities initially reported that nine people were wounded in the incident, but later revised that number to eight. Then on Friday night, Kelly said nine bystanders were wounded.
Shortly after the incident, Bellevue Hospital reported that it was treating six victims for gunshot wounds. None of the injuries was considered life-threatening.
Police say Johnson used a .45-caliber semiautomatic handgun -- which held eight rounds -- and was carrying extra ammunition in his briefcase. He purchased the weapon legally in 1991 in Florida, but did not have a permit to carry it in New York City.
The former Manhattan resident did not appear to have had a criminal record, but authorities were still checking, Bloomberg added.
His neighbor, Gisela Casella, described Johnson as a quiet animal lover whose death left her "shocked."
"He was the nicest guy. He must have snapped or something. I don't know," she said.
His landlord, Guillermo Suarez, said he lived alone and that he'd seen Johnson leave the building around 8 a.m. in a suit.
By around 9 a.m., the shootings had prompted local and federal authorities to close several streets around Fifth Avenue and 34th Street, snarling traffic in the heart of Manhattan.
President Barack Obama learned about the incident around 9:30 a.m. from top aides, the White House said. The shooting did appear to be linked to terrorism, authorities said.
The Empire State Building is one of the most famous skyscrapers in the world and one of New York City's best-known tourist attractions.
Each year, about 4 million people visit the building's two observation decks. At more than 1,453 feet tall, the landmark building reaches more than a quarter-mile into the sky.
The area also typically has a large security presence.
"There's always a focus and concentration on the building," retired police officer Lou Palumbo said. "That building gets special attention."
The Empire State Building Co. said in a statement Friday that "the building is fully operational at this time" and that police are investigating the incident.
CNN's Rose Arce, Poppy Harlow, Mark Norman, Laura Batchelor, Rob Frehse, Leora Kapelus, Pauline Kim, Khara Lewin, Rande Iaboni, Eden Pontz and Dana Garrett contributed to this report.
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