The New York City medical examiner has ruled that a subway rider was killed by a chokehold after a fight with another passenger that was caught on camera.

Officials say Jordan Neely’s death was caused by homicide, from “compression of neck (chokehold)”.

Video of the incident shows Neely, 30, struggling as another man grabs him and holds him on the ground.

Police have questioned and released the 24-year-old US Marine who restrained the passenger.

Homicide means a death caused by another person, but is not necessarily a murder. It is now up to police and prosecutors to determine if charges are warranted.

“As part of our rigorous ongoing investigation, we will review the Medical Examiner’s report, assess all available video and photo footage, identify and interview as many witnesses as possible, and obtain additional medical records,” a spokesman for Manhattan district attorney Alvin Bragg said in a statement following the ruling.

“This investigation is being handled by senior, experienced prosecutors and we will provide an update when there is additional public information to share,” he added.

The incident happened on Monday afternoon on the F-line train in the SoHo section of Manhattan.

On Wednesday, a rally for Neely was held on the train platform near to where he died. “Justice for Jordan Neely,” the crowd chanted, according to CBS News. “If we don’t get it, shut it down.”

A video that was captured by a freelance journalist on the train shows the former Marine holding the 30-year-old man, who was said to have been acting erratically – around the neck for two minutes and 55 seconds. Two other riders are also seen restraining his arms. All three later let go of the man, who is then seen lying motionless on the floor.

Police sources told CBS News that the man who died was throwing trash and yelling at passengers. Neely was a Michael Jackson impersonator and was living on the streets, according to US media.

Officers arrived at the scene at about 14:27 local time and found the man unresponsive. He was later taken to hospital, where he was pronounced dead.

Juan Alberto Vazquez, the freelance journalist who filmed the incident, told the New York Times that the deceased man was screaming on the train before he was restrained.

“‘I don’t have food, I don’t have a drink, I’m fed up,'” the man screamed, according to Mr Vazquez. “‘I don’t mind going to jail and getting life in prison. I’m ready to die.'”

He added the rider was frightening, but had not assaulted anyone. At the time of the incident, Mr Vasquez said he did not believe the man would die.

“None of us were thinking that,” he told the New York Times. “He was moving and he was defending himself.”

New York Governor Kathy Hochul called the video “deeply disturbing, and that causes a lot of fear for people”.

She said the state would work with the city to determine whether homelessness and access to mental health services “were a factor here”.

The mayor’s office also released a statement saying that despite the many unknowns factors, “we do know that there were serious mental health issues in play here”.