Police say three suspects opened fire on a 15-year-old boy near the intersection of South 29th and Morris streets around 7 p.m.
"Based on ballistic evidence, we know at least 16 shots were fired from three separate caliber semi-automatic weapons," said Chief Inspector Scott Small with the Philadelphia Police Department.
According to Small, the boy was in the backyard with family and friends when the gunmen unleashed a barrage of bullets.
The teen was shot multiple times and later pronounced dead. Small says some bullets even penetrated the home.
The suspects were able to get away in a white vehicle, witnesses told police.
Small said the boy did not live at the home. It's unclear what sparked the shooting.
Earlier in the day, police say two men were found dead inside a home on the 2900 block of Rosehill Street.
A 42-year-old man was found shot multiple times in a bedroom. Another man was found shot in the head and chest in the hallway of the home. No weapons were recovered at the scene.
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Around 2 p.m., police say a 25-year-old woman and a 29-year-old man were both shot inside a vehicle on the 200 block of Rubicam Street. The woman later died at the hospital. The man is expected to survive, police say. A toddler in the car was not harmed.
"There was a small child, a baby between one and two years of age, a female in the back seat, and miraculously she was not struck by gunfire," said Small.
And early Monday morning, police say a 24-year-old man was shot and killed around midnight on the 500 block of West Hill Creek Drive, and around 8:30 p.m., a 54-year-old woman was shot to death at a drug rehab facility on the 4200 block of Ridge Avenue.
No arrests have been made in connection with these shootings. Anyone with any information is asked to call police at 215-686-TIPS.
Monday's seven murders bring the unofficial homicide total for the year to 61.