It happened Monday morning in front of 735 Broadway.
The 20-year-old victim was walking down the street when the man walked up behind her.
Police say the man pulled her hair and slapped her head and buttocks, knocking her to the ground.
Bystanders watched in shock before a group of women behind her stopped to help and called 911.
"I saw the video as well, which was scary and very disturbing," said NYU graduate student Ashlyn Prieto. "So, it's definitely something to be more on the lookout, especially as my commute towards the park, especially because that was exactly like route that I would take. So it was very scary."
Police say they later arrested 45-year-old James Rizzo on Tuesday, and charged him persistent sexual abuse, forcible touching and assault.
They say they were called for a man sleeping in a building. Investigators then made the connection to Monday's attack, and arrested Rizzo.
He did not comment as he was led out of the 6th precinct in handcuffs on Tuesday night.
"I've always been concerned about safety a little bit, but definitely seeing something happen like that, it brings it to my concern more," said NYU freshman Rachel Rosenberg.
NYU says it is offering support to the student, and are pleased that the suspect is in custody.
"The University is pleased that a suspect has been apprehended in the attack on one of its students that took place Monday morning on a Broadway sidewalk," NYU spokesperson John Beckman said. "We take this incident very seriously. We are continuing to offer support to the student, and our Campus Safety Department assisted the victim and worked with the police investigating the incident."
Investigators are now trying to determine if Rizzo is responsible for other random attacks on female students at NYU.
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