Jeffrey Johnson has been identified as the gunman responsible of this morning Empire State Building shooting.

Jeffrey Johnson, 53, a disgruntled employee, returned to his former workplace and fatally shot his ex-boss three times in the head, sparking early-morning chaos and multiple other injuries near the Empire State Building.

But he was scuppered in his plans to escape after a construction worker saw the killing, chased him down the street and alerted police, who shot the gunman dead.

In the rush-hour ruckus, nine passersby were injured, including four who suffered gunshot wounds. Two people – the gunman and his former boss – were killed.

The deadly dispute horrified tourists and workers swarming the area around 34th street and Fifth Avenue which, at the height of summer, is experiencing its busiest few weeks.

Jeffrey Johnson had visited clothing retailers Hazan Imports, where he had been an accessories designer before he was fired as it downsized last year, on 33rd Street and Fifth Avenue at 9:00 a.m.

He was dressed in a smart grey suit and was carrying a briefcase, the New York Daily News reported.

Jeffrey Johnson returned to his former workplace and fatally shot his ex-boss three times in the head, sparking early-morning chaos and multiple other injuries near the Empire State Building

After his former boss, identified as 41-year-old Steven Ercolino, came out into the street to talk with him, Jeffrey Johnson shot him three times in the head and ran from the scene with his .45 caliber handgun hidden in a bag under his arm.

But he was followed a block north by a construction worker who had witnessed the deadly shooting and alerted two police officers on duty outside the Empire State Building.

When the gunman pulled out his firearm and aimed at them, they shot him dead.

During the gunfire, four people were shot and a total of nine people were injured. The seven men and two women were whisked away to nearby hospitals, where some are undergoing surgery.

In a press conference near the scene, Commissioner Ray Kelly and Mayor Michael Bloomberg said some of the nine people who were injured may have been hit or grazed by police gunfire.

The two officers fired a total of 14 rounds, AP reported. Jeffrey Johnson’s semi-automatic weapon was equipped to fire at least eight rounds; at least one round was left in the clip, police said.

It is “not likely” any of the victims will die, Commissioner Ray Kelly said. None are children or elderly.

When asked if the construction worker was the hero, Mayor Michael Bloomberg responded: “He did what he should have done. When he saw something, he said something and then turned it over to the professionals.”

Ray Kelly and Michael Bloomberg added that it was too early to say if Jeffrey Johnson was legally permitted to be carrying a gun, but early reports did not indicate he had a criminal record.

Witnesses recounted the chaotic scene during rush hour in an built-up area swarming with workers and tourists.

“The gunshots were like a movie scene, everybody running in every direction and you can hear the gunshots everywhere not knowing where to run,” witness Suzy El Ayoubi said on Twitter.

Aliyah Imam told Fox 5 News that she was standing at a red light when a woman next to her fell to the ground after being hit in the hip. She claimed the gunman was “shooting indiscriminately at people”.

Witness Kay Hudson, who said she was three feet away when a man was shot, said she heard seven shots then saw a man carrying an orange helmet lying on the ground.

Kay Hudson said she began shouting for people to run and started fleeing down 33rd Street.

Jill Greenwood, who works as an account supervisor at Prosek Partners in the Empire State Building, told the Wall Street Journal that she heard several gun shots beginning at 9:04 a.m.

She said that people inside the building began yelling because an echo from the shots made it sound like the shooting was happening inside the building.

“We heard these gunshots, it sounded like fireworks. So, we both got up and went to the window and looked down,” Jill Greenwood, 30, told the WSJ.

Helicopter footage apparently showed the gunman lying on a stretcher in handcuffs, before officers placed a white sheet over his body.

A fire department spokesman said it received a call about the shooting just after at 9:00 a.m. and that emergency units were on the scene within minutes. The FBI confirmed it was not terror related.

“What I want to do is assure everybody this is nothing to do with terrorism,” Michael Bloomberg said at the press conference.

“Thank God nobody else was seriously injured. Again, there’s an awful lot of guns out there,” the mayor, a staunch advocate of stricter gun laws, added.

Coincidentally, just minutes before the shooting, Michael Bloomberg had warned about the dangers of “too many guns on the streets” on his weekly radio show.

While discussing proposed tougher gun laws in Albany shortly before 9:00 a.m., he said: “The argument guns don’t kill people, people kill people is one of the most disingenuous things you can say.”

“It does take a person to pull the trigger, but if they didn’t have the gun… We are the only developed country in the world with this problem,” the mayor continued.