A gunman with mental health issues opened fire in a central Manhattan skyscraper on Monday, killing four people including a policeman before apparently taking his own life, officials said.
Mayor Eric Adams said the fallen police officer was a 36-year-old immigrant from Bangladesh.
Two other males and a female died and another man remained in a critical condition, officials said without giving any preliminary motive for the shootings.
An NFL employee was stable after being 鈥榮eriously injured鈥� in the attack, ESPN reported, quoting an internal memo from league commissioner Roger Goodell.
A fifth victim was in critical condition after being shot, Eric Adams told a late-night press briefing at a nearby hospital.
The gunman was caught on surveillance footage leaving a black BMW and carrying an M-4 rifle, police commissioner Jessica Tisch told the news conference.
On entering the building, he immediately opened fire on a police officer before 鈥榮praying the lobby鈥� with bullets, she said.
The gunman then took an elevator to the 33rd floor of Rudin Management, which owns the building, and continued his spree before apparently shooting himself. He was later discovered by officers next to his weapon.
The office tower block at 345 Park Avenue 鈥� home to the National Football League, hedge fund giant Blackstone, and auditor KPMG 鈥� was apparently targeted by the gunman, who is believed to have acted alone, Tisch said.
The police commissioner identified the shooter as Shane Tamura from Las Vegas and said a revolver, ammunition and magazines were found in his聽vehicle.
Tamura had a history of mental health issues, she said.
The incident began around 6:00pm (2200 GMT) when reports of gunfire prompted hundreds of police to swarm a busy office district on Park Avenue, an area popular with tourists and businesspeople.
A worker from a nearby office building wept as she left the area after a local lockdown was lifted.
Another office worker described the gunman going floor-to-floor as staff prepared to leave for the day.
鈥榃e lost four souls to another act of senseless violence,鈥� the city鈥檚 mayor said, excluding the shooter, who died by an apparently self-inflicted gunshot.
CNN and NBC cited unnamed officials as saying the shooter had a grievance with the NFL and its handling of CTE, a brain condition linked to head trauma.
The gunman had a note in his pocket saying he suffered from CTE, the news channels said, quoting a source with knowledge of the investigation.
Office worker Shad Sakib said that he was packing his things to leave work when a public address announcement warned him and his colleagues to shelter in place.
鈥楨veryone was confused with like, 鈥榳ait, what鈥檚 going on?鈥� And then someone finally realised that it鈥檚 online, that someone walked in with a machine gun,鈥� the witness said.
鈥楬e walked right into a building right next door. We saw the photo of him walking through the same area that I walked through to get lunch here.
鈥榊ou would think it won鈥檛 happen to you, and then it does.鈥�
Another witness, a woman who declined to give her name as she left the vicinity of the shooting, said: 鈥業 was in the building. He went floor by floor.鈥�
A second woman wept as she left the scene.
There have been 254 mass shootings in the United States this year including Monday鈥檚 incident in New York, according to the Gun Violence Archive 鈥� which defines a mass shooting as four or more people shot.
