NEW YORK (CBSNewYork) — The NYPD says a black woman sprayed several white people with a chemical substance near a pair of subway stations in upper Manhattan Friday afternoon.

Police tell CBS2 the incident, the latest in a trio of alarming underground assaults that have gripped the city’s transit system, is being probed as a possible hate crime.

Investigators say the woman first sprayed someone on a platform inside the station at 125th Street and Lenox Avenue around noon. She then fled the station and sprayed another four people on the sidewalk between Lenox and St. Nicholas Avenues.

An hour later, police say she sprayed another woman outside the station at 96th Street and Broadway.

“It lights up your whole face on fire,” Joshua Smith, who was sprayed on his way home from a doctors appointment, said. “Your sinuses, your throat feels like it’s closing up. It’s rough.”

The chemical spraying comes on the heels of a pair of violent incidents in the city’s subway system nearby. Since Thursday, two attacks were reported at the 125th Street and Lexington Avenue station in East Harlem. A 30-year-old man was charged with assault in one incident, but police are searching for the suspect in the other.

Julio Leonardo allegedly punched a conductor on the 4 train platform shortly after midnight Friday. Police said Leonard had been holding the doors of a train. When the conductor asked Leonard to stop, he allegedly punched him, and the conductor punched back.

A few hours earlier at the same station, another man was slashed in the face. Police said the suspect and victim in the earlier incident were strangers and got into an argument after bumping into each other.

Earlier this week, the NYPD said overall, crime in the city is down, but in the transit system, it’s up – a 5.6 percent increase this February compared to the same time last year. So far this year, there’s been an average of six crimes a day across the entire transit system.

Police are looking for a black woman in her 30s or 40s who weights approximately 150 pounds and was last seen wearing a blue jacket and gray pants.

The NYPD’s Hate Crime Task Force has joined in the investigation, which is ongoing.