(NewsNation) — One of the eight teenagers shot at a bus stop in Philadelphia Wednesday night remains in critical condition, Deputy Police Commissioner Frank Vanore said at a news conference Thursday.

Doctors, though, are “optimistic” for the 17-year-old, who was shot nine times, Vanore said.

The Northeast High School students, ranging in age from 15 to 17, were waiting for the bus around 3 p.m. Wednesday when three people emerged from a car and fired more than 30 shots, Kevin Bethel, the city’s police commissioner, said at a news conference Wednesday. Vanore told reporters that a fourth person was driving the car as it retreated from the scene.

Highway patrol officers recovered a 2018 blue Hyundai Sonata, which investigators believe was involved in the shooting. The Hyundai Sonata, which is now being processed by police, had been stolen.

In total 34 casings and three handguns were used by perpetrators, Vanore said.

Injured students have not yet been named.

All eight were taken to hospitals.

The Thursday news conference is scheduled for 1 p.m. ET.

This shooting marked the fourth on Philadelphia’s transit system in four days.

Police fielded numerous calls during the incident about a shooting on the highway near a Dunkin’ store, a police spokesperson said.

Police confirmed to NewsNation that the shooting happened in the area between Rising Sun Avenue and St. Vincent Street and did not occur inside a bus. Two buses were hit by gunfire, though.

“We will not be held hostage,” Mayor Cherelle Parker said Wednesday. “… We will use every legal tool in the toolbox to ensure the public health and safety of the people of our city.”

School District of Philadelphia Superintendent Tony Watlington Sr. said officials were “absolutely heartbroken and angry that innocent children walking home from school would be impacted by gun violence, and we agree with the mayor: Enough is enough.”

No arrests had been announced as of Thursday morning.

NewsNation’s Steph Whiteside Associated Press contributed to this report.