Abigail Gillon, 12, was riding an electric scooter with her best friend, 11-year-old Isabella Jones, on Saturday afternoon around 2:30 p.m. when the girls were hit by a car on Lehr Boulevard near Concord Road.
Both girls were rushed to the hospital with life-threatening injuries.
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"One without the other was very rare, joined at the hip. If you got one, you most likely got both," said Kevin Pierce, the girls' coach at Ridley Township Swim Club. "It broke my heart. You don't wish this on anybody."
Gillon's family says she passed away from her injuries on Monday.
Girl dies from injuries in scooter accident; best friend critically hurt
"There's going to be a big void on our team," said Pierce.
He described Jones as a bundle of energy and said Gillon was a joy to be around.
"The type of kid that always walked in the pool with a smile on her face. Could have been 45 degrees and rainy, and she'd show up to swim practice and she'd be laughing and smiling," said Pierce.
On Tuesday night, the community held a balloon release during vigil at Ridley Middle School.
"Today we gather to honor and remember someone who was such a special soul," said Brianna Newmiller, who was Gillon's neighbor. "This morning, Abigail had her hero walk down the halls of DuPont Hospital. Through the gift of life, she was able to save another 12-year-old girl's life by donating her liver, pancreas, and both kidneys."
The entire Ridley community is banding together, donating tens of thousands of dollars to help both families.
"We're in the Ridley community. We're very close to the girls that were injured," said Jen Babe-Konstandinou of Dino's Style Pizza, one of several businesses raising funds.
Babe-Konstandinou says her granddaughter has been friends with the girls since preschool.
"Ridley strong, one of us hurts, we all hurt. That's just, that's our motto," she said.
The families are grateful for the outpouring of support.