The 35-year-old man who filmed a viral video that shows an Asian man being attacked in a NYC subway station told The Post he believed the incident was vigilante justice not ethnic hate.

The videographer, who asked to remain anonymous, said he was on his way home from work around 3:30 p.m. Friday when he saw the Asian man being held from behind on the A/C platform in the Fulton Street station.

“I said, `What are you doing? Why are you holding that guy?” the filmer recalled. And in response he claimed the Asian man had just tried to sexually assault a woman in a subway car so he pulled him off onto the platform.

The black man who was holding the alleged assaulter then said, “‘Call the cops,’” according to the videographer.

When he called 911, cops said they’d be right there, he recalled. But five minutes went by and the police didn’t come.

“The guy holding the Asian gentleman said, ‘Where are the cops? Where are the cops?” he said. “So I called the cops a second time.”

The man who was being held was trying to get away, he said.

“Although the video doesn’t show that, he was trying to get away the entire time,” the filmer said. “There were other people around. One girl says, ‘I’ll go upstairs and get them.’ She came back down and said ‘They’re coming.’”

But police officers didn’t arrive for about 20 minutes after his first call. Meanwhile, as new onlookers arrived they were told the man had tried to assault a girl on the train.

The man who was being held allegedly said, “‘Yeah, so what? Do you have it on camera?” the videographer recalled. 

Around this time, two other men suddenly attacked the alleged assaulter, he said.

One of the men slaps the Asian man in the face, causing his body to go limp, the video shows. Then, a second man delivers a series of punches to his head. Some in the group cheered and applauded the beating.

One of the men who struck the straphanger can be heard saying that he has a daughter before his hand makes contact with the man’s face.

“I got a daughter,” he said. “If the cops lock me up, I’m paying my own bail.”

The video shooter said he and the man holding the alleged attacker were trying to calm everyone down.

“You hear the guy holding him saying, ‘Chill! Chill!’ and you hear me saying, ‘Stop,’” he said.

An NYPD spokeswoman said the department was aware of the video and was looking into it but didn’t have any information about what happened. The cops also said no complaints of sexual assault had been filed.

The footage was shared by the “Asian Crime Report” Twitter account Sunday and then retweeted by the NYPD Asian Hate Crimes Task Force with a callout for the victim to reach out.

It was not clear if cops talked to the Asian man as of Monday. It also wasn’t clear whether the incident was being investigated as a hate crime against an Asian New Yorker — a persistent problem since the onset of the pandemic, which some politicians labeled the “China Virus.”

The videographer said the violence might have been avoided if police had arrived sooner. He called the cops at 3:31 and the video was time stamped 3:49 and another five minutes went by before they arrived, he said.

The NYPD said in a statement that its officers arrived at the station by 3:34 p.m. and many involved in the incident were no longer present.

The department has since opened an investigation.

“Detectives alerted to video clips posted to social media on Sunday, showing a man being assaulted, are tracing the incident backwards from that moment on a Fulton train platform in their ongoing work to identify those involved, gather evidence, and find and interview all witnesses,” the statement said in part.

The videographer said the bottom line is the incident had nothing to do with ethnic hate.

He said the guys who struck the man were reacting to a man being accused of sexually assaulting a female on a subway car.

“This thing has gone completely bonkers,” he said.

“The guy holding him never attacked him and he didn’t know those guys [who hit him.] The most important part in all of this is that none of this was race related.”