PHILADELPHIA (CBS) --as they tried to break up a car meetup that shut down Interstate-95 near Penn's Landing that included drivers doing burnouts and racing and setting off fireworks.
"The behavior over the weekend is not only unacceptable but it will not be tolerated," Philadelphia Police Commissioner Danielle Outlaw said.
A detail of officers was scrambling to keep up as streets filled with
"Property was destroyed, officers and civilians were assaulted and countless, countless individuals had their lives put at risk because of the behavior that we witnessed," Outlaw said.
State Police estimated 1,000 people shut down I-95 at Penn's Landing where there were more stunts, fireworks were set off and shots were fired.
A news conference brought stiff warnings from police and prosecutors.
"You gotta cut out the street racing," District Attorney Larry Krasner said.
Police outlined at least five so-called hot spots on Saturday night — in the Northeast and North Philadelphia where car meets took over intersections.
Investigators confirm one arrest was made, but warn more are expected.
"If anyone was participating in this activity, do not think for one moment that you got away with it. We are not done," Outlaw said.
Saturday night's chaos ended on the shoulder of I-95 when state troopers shot and killed 18-year-old Anthony Allegrini Jr. of Glen Mills
Investigators allege Allegrini failed to yield in his Audi and struck two troopers.
A state police captain said one trooper fired a single shot through the windshield, killing Allegrini Jr.
Video from social media too graphic to show reveals an armed trooper standing over a wounded Allegrini — medics would later pronounce him dead right on the highway.
As prosecutors promise transparency, an attorney for the Allegrini family says they are opening their own investigation into state police's use of force.
"You're dealing with someone that wasn't a racer. You're dealing with someone that was not making burnouts or blocking up 95, he was simply a spectator and as these races go, there were plenty and thousands of spectators," Enrique Latoison, of Latoison Law, said.
Meanwhile, Outlaw said her officers were outnumbered this weekend, but promised it won't happen again.
"People have gotten the sense that Philadelphia is the place to come, do whatever I want, trash it up, create all these safety issues for the residents here or people that want to come here and be here safely and leave and that's unacceptable," Outlaw said.
Outlaw said the department has to get better at tracking social media to keep tabs on the car meet-ups in real-time. She added the department has to be more proactive and not reactive.
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