Afterward, he saw the sidewalks littered with the wounded, including one person "dripping enough blood to leave a stream."
Wearing a suit and tie and carrying a briefcase, Jeffrey Johnson wordlessly walked up to the vice president, identified by officials as Steven Ercolino, put a gun to his head and fired three times, according to authorities and witnesses.
"Jeffrey just came from behind two cars, pulled out his gun, put it up to Steve's head and shot him," said Carol Timan, whose daughter, Irene, was walking to Hazan Imports at the time with Ercolino.
Johnson, 58, had traded accusations of harassment when Johnson worked there, Police Commissioner Raymond Kelly said; law enforcement officials said that Johnson had been angry that Ercolino wasn't promoting his products.
A construction worker who saw the shooting followed Johnson and alerted two police officers, a detail regularly assigned to patrol city landmarks like the 1,454-foot skyscraper since the 9/11 terror attacks, officials said.
There were conflicting accounts about whether Johnson fired at the police officers or just pointed the gun at them.
Kelly initially said the officers were fired upon, but later said police were investigating. Johnson can be seen on video reaching into a bag, pulling out a .45-caliber pistol and pointing it at officers, Kelly said.
The officers drew their weapons and fired 14 rounds, killing Johnson, Kelly said.
"These officers ... had absolutely no choice," Kelly said. "This individual took a gun out very close to them and perhaps fired at them."
Kelly said police may be responsible for some of the injuries because of the limited capacity of the gunman's weapon. Johnson's semi-automatic weapon was equipped to fire at least eight rounds; at least one round was left in the clip, police said. Another loaded magazine was in his briefcase.
Robert Asika, who was shot in the right arm, said he was "100 percent positive" that a police officer had shot him. He also said he saw Johnson fire his gun at the officers.
Asika, 23, sells tickets for the Empire State Building's observatory.
"When I woke up this morning, I didn't even want to go to work," he said. "Something told me not to go to work."
The wounded victims included five women and four men, aged 20 to 56, authorities said.
Ercolino's profile on the business networking site Linkedin identified him as a vice president of sales at Hazan Import Corp. It said he was a graduate of the State University of New York at Oneonta.
A man who answered the phone at Ercolino's home in Warwick, northwest of Manhattan, said he was too distraught to talk.
"He was a good son, that's all I can say," said the man, who didn't give his name.
Hazan Import Corp., imports women's clothing and accessories, according to public records. The business was incorporated in 1975 and lists Ralph Hazan, 61, Leon Hazan,35, and Isaac Hazan. 92, as presidents. Calls to the executives weren't immediately returned
Johnson worked at the company near the building for about six years and was laid off because of downsizing, Kelly said.
Even after he was laid off, Johnson would leave left his Upper East Side apartment building each morning in a suit, and often returned about a half hour later after going to get breakfast at McDonald's, his neighbors said.
"He was always alone," said Gisela Casella, who lived a few floors above him. "I always felt bad. I said 'Doesn't he have a girlfriend?' I never saw him with anybody."
His superintendent, Guillermo Suarez, said he lived alone in a one-bedroom apartment that he was subletting from someone else. He called him a "very likeable guy," who always wore a suit.
At the scene, New Yorkers took to Twitter and the photo-sharing service Instagram to post photos from the bloody sidewalk, just as they had less than two weeks ago when police shot a knife-wielding man on a Saturday night in Times Square. One office worker took an overhead shot of a pool of blood outside the Empire State Building.
"We were just working here and we just heard bang, bang, bang!" said Mohammed Bachchu, 22, of Queens, a worker at a nearby souvenir shop. He said he rushed from the building and saw seven people lying on the ground, covered in blood.
Queens resident Rebecca Fox, 27, said she saw people running down the street and initially thought it was a celebrity sighting, but then saw a woman shot in the foot and a man dead on the ground.
"I was scared and shocked and literally shaking," she said. She said police seemed to appear in seconds. "It was like 'CSI,' but it was real."
Hassam Cissa, 22, of the Bronx, said he saw two bodies on the ground and police applying a white cloth to a man's stomach wound.
Gunshots so close to one of the city's leading tourist attractions immediately prompted fears of terrorism, but federal officials said that wasn't the case, and a guard at skyscraper said it didn't involve the parts of the building where tourists gather to visit the skyscraper.
In 1997, a gunman opened fire on the 86th floor observation deck of the Empire State Building, killing one tourist and wounding six others before fatally shooting himself.
Metal detectors and bag searchers have been standard at the 102-story skyscraper since the 1997 shooting.
Millions of tourists visiting New York ascend its heights to gape over the city from its observation deck, made famous in films such as "Sleepless in Seattle." It was 1933's "King Kong" that showed a giant ape clutching Fay Wray and fending off airplanes atop the tower.
The skyscraper and its observatories remained open throughout the mayhem Friday, the building's owner said.
"This unfortunate event had nothing to do with the Empire State Building and with terrorism," said Anthony Malkin of Malkin Holdings.
Contributing to this report from New York were Alex Katz, Samantha Gross, Julie Walker, David B. Caruso, Adam Geller, Karen Matthews, Ula Ilnytzky and Anne D'Innocenzio.