Freelance photographer R. Umar Abbasi tells NBC's "Today" show that he wasn't trying to take a photo of the man, but was trying to alert the motorman to what was going on.
He says he's shocked that people nearer to the victim didn't try to help in 22 seconds before the train struck.
Abbasi's photo set off an ethical debate after it appeared on the front page of the New York Post. Ki-Suck Han of Queens died shortly after being pushed by a stranger onto the tracks Monday.
The NYPD was questioning a suspect. His name wasn't released.
(Copyright 2012 by The Associated Press. All Rights Reserved.)