Police Commissioner Richard Ross said nearly 70 people were at the party when the mass shooting happened around 10 p.m. at Paschall Playground, in the city's Eastwick section.
"There was nothing that suggested there was a fight that preceded this," said Ross.
"I just hear my son, who's screaming, 'Mom. Shot. Where are you?' I said, 'I'm home, I'm home. What happened?' He said, 'Somebody come and just shoot.' "
So far, no one has been arrested.
"How heartless must you be to pull the trigger that many times and hit that many people, knowing that would be the likely outcome?" Ross questioned.
Part of a greater statistic
Authorities noted 31 people were shot in Philadelphia over the weekend in 16 separate incidents, with six total fatalities. Ross said police are ramping up patrols.
Ross said police have pulled more than 800 guns off the streets — double the amount from 2015 — most of them .40 caliber, high-powered weapons.
"If you have one, please do not allow that gun to get into the hands of someone who will commit a crime with it," Ross added, "because the ATF will tell you that is a direct means of trafficking.
"We are not talking about a bunch of rinky-dink weapons," he continued. "We are talking about state-of-the-art weapons."
Discouraged by ease of access
Mayor Jim Kenney said Monday that he's "heartbroken" by the mass shooting and by the continued gun violence in the city. He's also frustrated by what he calls easy access to guns.
"The bottom line is that you can get a gun in this city faster than you can get a library card, and apparently the federal government and the state government believe people should have unfettered access to guns."
The mayor said he's at a loss as to how to change the mindset of people who resort to guns to settle disagreements.
"I've been to many graduation parties," the mayor said. "I've never thought of bringing a gun with me to a graduation party. I don't have the answer to changing that mindset."
Kenney believes the city's investments in education, summer jobs and activities for youth are the best way to address the problem over the long term.
Ross said they will add extra officers to patrol early morning hours during weekends, and reorganize Operation Pinpoint, which focuses on high-crime districts.
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