Officers responded to 3511 Boston Rd. in Williamsbridge just before 4 p.m.
Upon arrival, officers found the 16-year-old victim, identified as Aliyah Williams, with multiple stab wounds to her head and body inside the location.
Police say the incident began inside the deli when the victim threw water on the suspect. The suspect then stabbed Williams multiple times outside of the the deli before fleeing.
She was taken to Jacobi Hospital in critical condition, where she was later pronounced dead.
A 19-year-old, who doesn't want to be identified, is an EMT-in-training who tried to render aid.
"She's moving a lot, I tried to tell her to calm down, because if you keep moving around you're going to lose a lot more blood than you expected," he said.
Police are investigating whether Williams was called to the location, prior to the stabbing, by people she may have had a long-standing dispute with.
Later Wednesday afternoon, police announced the arrest of a 17-year-old suspect on charges of murder, manslaughter, and criminal possession of a weapon.
The victim's loved ones spoke out after her death.
"I never expected this to happen to her because she's not a bad kid, you know?" said the victim's grandmother Rose Anderson. "She's a people person and she's always in our hearts. Marisol, rest in peace."
The owner of a baking supply store, who provides summer jobs for teens, says he's angered by the violence that took place in the store next door. It's identified as a deli but he says its known in the neighborhood as a smoke shop.
"And now I have six to eight kids with something so traumatic, and we're failing our kids," the owner said.
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