The incident happened around 2 p.m. on Feb. 22 on Gerard Avenue in the Concourse section.
Police announced Friday that 16-year-old Edgar Garcia is in custody in connection to the shooting.
NYPD Chief of Detectives Dermot Shea said Garcia is expected to be prosecuted as an adult.
"This is what this young girl is walking through ... I don't want to see that once in NYC. Period," he said.
Authorities say Garcia walked up to a group of people, pulled a gun and took aim at one of them -- a 19-year-old man. He fired three shots before taking off.
In video released by the NYPD this week, people on the sidewalk can be seen running or ducking for cover.
Another surveillance video obtained by WABC showed a little girl with a backpack walking home from school, right near where the gunman was shooting.
The terrified girl ran away and went toward the entrance of a building but found the front door was locked. She is seen remaining by the side of a woman before someone finally opened the door.
"My heart dropped when I saw the little girl running for her life," said Awilda Cordero, a community activist who is haunted by the image of the little girl and the man firing shots.
"If he did it now and he didn't care he'll continue to do it, so we need to get him off the street," said Cordero.
Fortunately, no one was injured in the incident. Police believe the incident stems from an ongoing dispute between two gangs.