A man and woman were shot on the evening of Friday, Sept. 12 at 82nd Street and Amsterdam Avenue on the Upper West Side. (Credit: CBS 2)

NEW YORK (CBSNewYork) — An off-duty New York State narcotics agent is facing charges following a shooting that injured two people on a crowded Upper West Side street Friday night.

“We just heard a pop and she just keeled over,” said witness Wendell Santiago.

Santiago told CBS 2’s Janelle Burrell he’s still in disbelief after a 31-year-old woman collapsed right outside of the juice shop he works at on the corner of Amsterdam Avenue and West 82nd Street.

“We thought it was a BB gun at first. Then we saw the actual bullet and the whole investigation, so it was actually pretty crazy,” Santiago said.