Police releasing a video of the suspect.
They say he stabbed 55-year-old Stanley Porter twice.
It happened near University Avenue and West 174th Street in Morris Heights on Saturday night.
"He just ran out from behind and stabbed me twice," Porter said. "I still don't understand why."
Porter says that after living years in the neighborhood he's now paranoid.
Porter says the injury still hurts - but he was able to walk all the way to the hospital the day of the stabbing.