A surveillance image of the man being questioned for allegedly pushing a man in front of a subway train in Midtown, killing him. (Credit: CBS 2)

NEW YORK (CBSNewYork) — Police on Monday night released new surveillance video in the search for a suspect who shoved a man onto the subway tracks for a train to strike him and kill him.

As CBS 2’s Lou Young reported, in a city built on subways, where millions move around town by train, it could have happened to anyone.

WCBS 880’s Rich Lamb reports https://newyork.cbslocal.com/wp-content/uploads/sites/14578484/2012/12/subway-push-rich-lamb-1-intern2.mp3

The incident happened around 12:30 p.m. at a subway station at 49th Street and 7th Avenue, just blocks off Times Square.

Ki Suk Han, 58, of Elmhurst, was hit by a southbound R train after he was pushed onto the tracks by another person.

The video shows the men arguing seconds before police say the suspect shoved Han to his death. The men are not believed to have known each other.

As of Monday night, the killer remained at large, and subway residents were reeling at the scene of the fatal confrontation.

1010 WINS’ Al Jones reports https://newyork.cbslocal.com/wp-content/uploads/sites/14578484/2012/12/subway-push-rich-lamb-1-intern2.mp3

The impact of the train could be heard almost a block away.

“I heard a commotion going on,” said witness Patrick Gomez. “The train was about three quarters into the platform. You know, it was slowing down by the point, but after it started slowly going to the platform, you almost heard like a thud, a thud, you know, like something was hit under the train.”

Han was taken to Roosevelt Hospital, but he is believed to have died at the scene, crushed in the narrow space between the train and the platform. It was a sight so terrible that the conductor had to be treated for trauma.

Witnesses said Han was still alive in the moments after he was struck.

“He was moving, he was shaking his head up and down,” said Joel Parkington. “I left before he stopped breathing. When I was leaving, was still alive.”

At Han’s home Monday night, police delivered the awful news that he had passed away, and escorted a woman from the home on 57th Avenue in Elmhurst. Neighbors exchanged their shock.

And the entire city seemed to be shocked by a crime so random and senseless.

“How do you not think about it?” said Ann Campbell. “You hear stories of people falling in front of the subways all the time, and all it takes is someone just to come and push you right off the edge. That sounds awful. I can’t believe it actually happened.”

Police Monday night were searching for a person of interest, who is described as a black male in his 20’s or 30’s, around 5-feet-10, weighing approximately 240 pounds.

He was wearing a grey T-shirt, a down coat and a beanie-style knit cap.

The man is also described as having short dreadlocks.