Porshe Foster (Credit: Family photo)

UPDATED: 11/27/2012 6:04 p.m.

CHICAGO (CBS) — A 15-year-old girl was killed Monday night in a shooting in the Southwest Side Chicago Lawn neighborhood, police said.

Porshe Foster — who was a sophomore in high school, a straight-A student, an aspiring architect, and an athlete — was in the backyard of a home in the 7000 block of South Campbell Avenue with several people when an unknown male approached and opened fire on the group, striking the her in the back about 9:15 p.m., police said.

The girl was taken in critical condition to Advocate Christ Medical Center in Oak Lawn where she later died, police said.

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“There has to be an end to this foolishness. It has to stop. It has to stop somewhere. She didn’t deserve it at all,” her mother, Bonita Foster said.

Porshe was struck by a single bullet, but those who live in the house where she was killed said two dozen more gunshots were also fired. It’s the kind of intense gunfire that strongly suggests someone was being targeted, perhaps one of the young men with whom Porshe was talking.

Keith Terrell said, “I heard 15 to 17 shots, and bullets were still coming; they were still coming.”

In all, Terrell said 25 bullets riddled the house Porshe was visiting when she was killed. She was in the backyard, talking with friends, when someone started shooting.

Porshe ran inside and collapsed.

“She was bleeding from her back. I’m like, ‘Oh my God, she’s shot,’” Terrell said.

It was unclear what the shooter’s motive was, or if the girl was his intended target, police said.

“She didn’t have no type of troubles with anybody. She wasn’t a threat to nobody,” Terrell said.

No one was in custody as of Tuesday night.

“Someone in that backyard knows information whether they had beef with somebody, or whether it was gang-related,” said community activist Andrew Holmes. “They need to give up this information so this person can be apprehended.”

For Porshe’s mom, losing any of her six children has always been one of her biggest fears. Porshe was the youngest child.

“I’d think about it all the time,” said Bonita Foster. “Here we are and this is going to follow us for the rest of our life. She was only 15, and didn’t get to live her life.”

Porshe’s family had already started a fund to make sure she could attend her senior prom. And for Christmas, they planned to surprise her with a new guitar, an instrument she wanted to learn.

“We hid it in our brother’s closet, and she didn’t know she got it,” said Porshe sister, Robyn Foster. A surprise Sweet 16 birthday party was also in the works.

But those hopes and dreams died in a hail of bullets; gunfire intended for someone else.

“We think we’re going to have each other for life, but it don’t work out like that,” Robyn said.

With so much neighborhood violence, Porshe’s family had talked about what they would do if someone died. They don’t plan to have a typical funeral–no casket, no mourning. Instead, they will have a celebration of Porshe’s life–the 15 years they spent with her and loved her.