The shooting happened Friday at the Mill Creek Rec Center on the 4700 block of Brown Street around 1:30 p.m.
Police said Tiffany Fletcher, 41, was caught in the crossfire of a nearby gun battle.
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She was rushed to the hospital and placed in critical condition, but died just after 7 p.m.
During a news conference Monday, officials said police officers were in the area at the time of the shooting and ran toward the gunfire.
Police arrested a 14-year-old boy in connection with the deadly shooting. He is now charged with murder, officials said.
They also found a ghost gun in the trash, which they believe he ditched right after the shooting.
On Monday night, Fletcher's mother, Geraldine, held a photo of her daughter while demanding justice for the killing.
"Put away for life, that's what I would like to see," Geraldine said.
Gina Fletcher, Tiffany's niece, feels the same way.
"You should be sitting behind bars with whoever else that was affiliated. Age ain't nothing," Gina said.
Geraldine remembers how beautiful her daughter was when she was born.
"When she was a baby she didn't look like a real baby, she looked like a doll," Geraldine recalled. "She was a person who was always trying to help somebody. She was a person about love and caring."
Geraldine says she came face-to-face with her daughter's alleged killer moments after the gunfire erupted outside the rec center.
"He stopped with a little slow run and said, 'They shooting at me.' And I said, 'Don't look at me telling me. I don't want to hear that.' I got one of my sons killed by a gun and then you gonna say that not knowing it was Tiffany and they shot her," recalled Fletcher.
During the news conference, officials said they believe shots from the ghost gun are what killed Tiffany Fletcher.
The mother of three boys just started working at the rec center this summer and was beloved in the community.
Police are now searching for two to three other suspects in the gun battle.
Anyone with information about the shooting is asked to call police.