The shooting happened on June 14 on Greenland Drive in Fairmount Park during a pop-up party with about 200 attendees.
Seventeen-year-old Isya Stanley was killed when two suspects were shooting at each other during the party.
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Four other teen victims were hit by the gunfire and suffered non-fatal injuries, police said.
During a news conference on Thursday, top city leaders announced the arrest of 17-year-old Zayaan Carroll, who was allegedly one of the gunmen involved. Police are still searching for a second suspect.
Investigators credit good police work and the community's help in bringing an arrest in this case.
WATCH: Police announce arrest in deadly shooting at summer pop-up party
Police announce arrest in deadly shooting at summer pop-up party
Authorities say a recent traffic stop led to the recovery of a gun and the seizure of a cell phone. Officers were able to find information on the phone that would lead to Carroll's arrest on Wednesday.
"The telephone led us to the defendant in this case. And then when we got on the defendant's telephone, it linked him to statements made about this crime," said Assistant District Attorney Anthony Voci.
Voci noted that the gun was used in the pop-up-party shooting.
Top police brass vowed to continue hunting down individuals involved in violent crime.
"We're going to work tirelessly to continue to go after those individuals who cause harm in our community," said Philadelphia Police Commissioner Kevin Bethel.
Less than a month later on July 4, nine people were shot during another large party in Southwest Philadelphia. Maurice Quann, 19, was killed and eight others suffered non-life-threatening injuries.
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Police said Quann and Stanley knew each other and he helped to promote the Fairmount Park party.
The shooter in the Southwest Philadelphia shooting remains at large.
Anyone with information on the second suspect is asked to call police at 215-686-TIPS.