Police have a 30-year-old former deli worker in custody believed to be the suspect who pushed a subway rider off the platform and into the path of an oncoming train at 49th Street after an argument.

Law enforcement sources say the suspect has made statements to detectives implicating himself in the deadly push.

A law enforcement official told NBC 4 New York the man is suspected of pushing 58-year-old Ki-Suk Han off the platform at the N, Q, R station Monday afternoon. Han was hit by a southbound Q train and died.

Witnesses told police the suspect was mumbling to himself before he and Han began arguing on the platform.

A bystander recorded part of the fight between the two men and turned the video over to police, who released it to the public Monday night, and received several tips. The man who allegedly pushed Han is heard cursing and saying, in substance, "Leave me alone... stand in line, wait for the R train and that's it."

He then pushed Han onto the tracks, police said. Han tried to climb back up onto the platform but died after getting trapped between the train and the platform's edge.

A law enforcement official tells NBC 4 New York that co-workers from a nearby deli where the suspect works tipped off police that their colleague might be the subway pusher after they recognized his voice from video.

Investigators then saw the man on surveillance video in the street talking to street vendors outside the subway station, and when they went back to the area Tuesday, he was there, speaking with the same vendors, sources said.

One of the newsstand vendors told NBC 4 New York the suspect was a well-known face in the area and that he spoke to her Tuesday morning.

"I showed him the picture [released by police Monday] and he goes, 'Oh, that's not me,'" said Elizabeth Williston. "I said, 'Yeah, that's you!' Because yesterday, he had the beard, the hair. But today, he had shaved his head, shaved his mustache and everything."

Subway pushes are unusual. Among the more high-profile was the January 1999 death of Kendra Webdale. A former mental patient admitted he shoved her to her death.

Following that, the state Legislature passed Kendra's Law, which lets mental health authorities supervise patients who live outside institutions to make sure they are taking their medications and aren't a threat to safety.