Following an altercation on the New York tube during which a man was placed in a chokehold, police are looking into the incident.
A fellow rider’s restraint of a 30-year-old man who was allegedly acting abnormally led to his death.
He is shown on camera resisting as another man grabs him and holds him down.
The 24-year-old US Marine who detained the passenger has reportedly been questioned by police. Since then, he has been freed from custody.
Police said they are still looking into the event, and a cause-of-death report from the medical examiner is still awaited.
Both men’s names have not been made widely known.
On the F-line train in Manhattan’s SoHo neighbourhood, the incident occurred on Monday in the late afternoon.
The 30-year-old man is seen being held around the neck by the former Marine for two minutes and 55 seconds in a video that was recorded by a freelance journalist on the train.
He is also seen having his arms restrained by two other bikers. Later, all three released the man, who was seen lying motionless on the ground.
Police sources told BBC’s US news partner CBS that the 30-year-old was acting erratically on the train, allegedly throwing trash and yelling at passengers.
They added that officers arrived at the scene at around 14:27 local time (19:00 BST) and found the man unresponsive.
He was later taken to hospital, where he was pronounced dead
The man said, “I don’t have food, I don’t have a drink, I’m tired,” according to Mr. Vazquez. “I don’t mind getting life in prison or going to jail. I’m ready to pass away.
He stated that although the motorcyclist was terrifying, he had not attacked anyone. Mr. Vasquez claimed he did not think the man would pass away at the time of the occurrence.
“None of us were thinking that,” he claimed to the New York Times. He was protecting himself while moving and moving.”
Juan Alberto Vazquez, the freelance journalist who filmed the incident, told the New York Times that the deceased man was screaming on the train prior to him being restrained