Four people shot outside Empire State Bldg.

The two men at the center of a fatal shooting outside the Empire State Building on Friday had brushed shoulders for years — often literally, two large egos stuffed into a small office — and yet could hardly have been less alike.

Neighbors and co-workers described them: Jeffrey T. Johnson, 58, a slight, meticulous artist, the first one to work in the morning and the last one out, without so much as a look outside for fresh air in between; Steven Ercolino, 41, a well-built, confident salesman used to getting what he wanted when he wanted it. The artist chafed at what he saw as the salesman’s casual bossiness, they said, and the two never got along.

Years passed this way at the company, Hazan Imports, which sold handbags and belts, until Mr. Johnson was laid off almost two years ago.

And yet, the casual observer would not have known it, to look at him. He put on the same suit every morning: the Upper East Side’s own Willy Loman, dressing for a job he no longer had. He picked up his newspaper on the front stoop and walked two blocks to McDonald’s for breakfast.

Months after his dismissal, he showed up at the building where he once worked, across West 33rd Street from the famous skyscraper, and confronted the salesman, a much larger man, in an elevator. The two came close enough to blows — Mr. Johnson throwing an elbow, Mr. Ercolino grabbing his throat and threatening him — that it was reported to the police.

The feud ended Friday. Mr. Johnson left his East 82nd Street walk-up in his suit, as he did every other day. And Mr. Ercolino took the PATH train from Hoboken, N.J., where he lived with his girlfriend, to the West 33rd Street building near Fifth Avenue. A co-worker saw him and shouted for him to wait, then they walked toward the entrance together. They were almost there when the co-worker, Irene Timan, 35, saw Mr. Johnson lurking behind a white van.

“I saw him pull a gun out from his jacket, and I thought to myself, ‘Oh my God, he’s going to shoot him’ — and I wanted to turn and push Steve out of the way,” Ms. Timan said. “But it was too late. Steve screamed, Jeff shot him, and I just turned and ran.”

Mr. Ercolino died. Mr. Johnson was shot to death moments later by two police officers after pulling the gun again and aiming at them, according to the police; nine people were wounded in gunfire.

All because of — what? Those who worked with both men struggled to describe the root of their animosity hours later.

“You chalk it up to two guys being around each other too much,” one longtime co-worker said of their hostile relationship.

Mr. Johnson was born in 1953; he said he had a Japanese mother and an American father. A childhood love of comic books seems to have forged his career. He had returned to the form in recent months, posting intricate illustrations of cars on a Web site he ran, stjollysart.com, as a way to make money selling T-shirts.

“This gallery of illustrations,” he wrote in a caption beneath his rendering of a muscle car, “is an homage to all the great art and artists featured in all the automotive comics my friends and I pored over as kids during the ’60s.”

He attended Ringling College of Art and Design in Sarasota, Fla., from 1978 to 1980, leaving a year shy of the three years required for a certificate, the school said Friday.

Sometimes he spoke cryptically of past military service. “He was in the Marines, or Special Forces,” the co-worker said. “He was in Vietnam. There’d be things he’d say — ‘Oh, that’s not the way it’s done,’ or ‘I can’t talk about that.’ ”

Mr. Johnson told a former landlord, Kathleen Walsh, that he was a sharpshooter. Several branches of the military, including the Army, the Navy and the Marines, said Friday there was no record of his service, but a law enforcement official said he may have served in the Coast Guard.

Around 2005, Mr. Johnson joined Hazan Imports, a company founded about 40 years ago by the brothers Isaac and Ralph Hazan.

“This guy was very eccentric,” the co-worker said. “He was so detail-oriented. If he had a free minute, he would start doing origami. The things that came out of his mind were so original and creative, you knew that his mind didn’t work the same way as normal people. But you worked with the guy so long, that you just chalked it up to Jeff being Jeff.”

Mr. Johnson told Ms. Walsh that he hated the work and was not paid enough.

Mr. Ercolino, a graduate of the State University of New York at Oneonta, arrived in 2005 as a vice president for sales, having worked at Betesh Group, which sold handbags and other products, and at the Jump Apparel Group. By the time he hired Ms. Timan a year later, the artist’s discomfort with the salesman was on full display.

The owner, Ralph Hazan, pulled Ms. Timan aside and warned that Mr. Johnson might be suffering from post-traumatic stress disorder. Everyone in the office “walked on eggshells” around him, co-workers said.

Not Mr. Ercolino. “If Steve needed something, rather than go to one of the owners, he’d go right to Jeff,” the longtime employee said. “ ‘I need a sample in blue, right away.’ And Jeff wouldn’t take orders from him.”

“As time goes by, you could walk down the hallway and see an elbow being thrown or a shoulder being shoved, or a comment.”

Mr. Johnson seemed unimpressed by the size of his rival, about 5 feet 10 inches tall and 220 pounds, six or seven inches taller than Mr. Johnson and twice his weight. “Steve is a very laid-back guy; he’s a salesman,” the co-worker said. “But Jeff is regimented, military, a chain-of-command type.”

Ms. Timan said of Mr. Johnson: “He would taunt Steve, push him.”

A decline in sales led to the sort of belt-tightening that occurred all over, and Mr. Johnson, who could be replaced with a lower-paid employee, was an easy target. “He didn’t freak out,” the longtime co-worker said. “He wanted to keep his computer; fine, no problem. There were no threats, none of that.” Once, the co-worker ran into Mr. Johnson on the street; he seemed fine.

Mr. Johnson was fastidious at his apartment, which he shared only with cats. He ran his vacuum early in the morning. One neighbor, Gisela Casella, 71, thought the man in the suit worked at a bank. “He was the nicest guy,” she said. “I never saw him with a woman, and I would always say to myself, Boy, he deserves a nice girlfriend.”

He seems to have spent more time drawing women than dating them. A series of six illustrations of an attractive woman on a motorcycle, on his Web site, describe a chance encounter in Florida in 1983, at a gas station. “Her blonde tresses fell just below the taut line of her shoulders and was being teased by a sea breeze coming off the bay,” Mr. Johnson wrote. He told her, “Nice bike,” and she replied, “in a soft, throaty voice, ‘Fast bike.’ ”

He went out for his breakfast every morning in his suit, returned with his McDonald’s bag and seemed to stay up on the third floor all day.

Months after he was let go, he returned to his old office building, on April 27, 2011. Ms. Timan was there when Mr. Ercolino entered, flustered, and told her what had just happened.

“Steve was leaving the elevator, Jeff was walking in, and Jeff elbowed him,” she recalled. “Steve had finally had enough, so he grabbed Jeff by the throat, and said, ‘If you ever do anything like this again, I’m going to kill you.’ ”

Ms. Timan told Mr. Ercolino to file a police report. “He went down to the precinct and called me from there, and he said, ‘You’re never going to believe this, but Jeff just left, and he filed a complaint against me!’ ” Both told the police the other had threatened him. According to the police, the artist blamed the salesman for not selling enough of the items he had designed.

Francis Ercolino, Mr. Ercolino’s father, said that he spoke with his son daily and that he never mentioned any problems at work. He said that Steven’s sister and two brothers, along with his nephews and nieces, were heartbroken.

“He was just a wonderful person,” he said. “Just write that. I have nothing else to say.”

After the scuffle in April 2011, there is no reason to believe Mr. Johnson and Mr. Ercolino saw each other again, until Friday. Mr. Johnson emerged from his building at the usual time and in the usual attire, said his superintendent, Guillermo Suarez, 72, whom everyone calls Bill.

“He said, ‘How you doing, Bill?’ and he never came back to the building,” Mr. Suarez said.

Mr. Ercolino, just back from a Mexican vacation with his girlfriend, walked toward the office with Ms. Timan, telling her he wasn’t feeling well. Ms. Timan spotted Mr. Johnson at the van.

“He didn’t say one word,” said Ms. Timan. “He just had the look of death, of evil, on his face.”

“He just started shooting,” she said, “and he did not stop.”