Hannah Bell was gunned down Friday night outside The Best Burger near Western Avenue and 77th Place, police said. Her killer remains on the run.
Family members spoke at the anger-packed news conference, where they pleaded for the public's help.
"I'm just reaching out for somebody, anybody, that heard anything, that knows anything that can bring this young man to pay for what he done," said the victim's mother, Samantha Mays. "It was wrong to take my daughter, she was innocent."
Other loved ones expressed anger over the violent act on a child in the community.
"When did it stop being safe for a teen to grab a burger? I wouldn't want this for my worst enemy," a loved one said.
On Sunday, a teddy bear surrounded by loving notes, balloons and candles was left at a memorial for Hannah. Dozens of people attended an emotional vigil for the teen that night.
Hannah's devastated mother nearly collapsed during the gathering. She was with the 15-year-old when the gunman opened fire..
"I walked to get my baby a burger 'cause she had to take her insulin shot and had to eat and...and they shot her," said Mays.
She recalled seeing a man in a hoodie but said she was ordering food -- her back turned when her daughter was fatally wounded.
"I don't know what I'm going to do without her. She was my rock. I was changing my life for her," Mays said.
Police were investigating whether Hannah was a target or simply at the wrong place at the wrong time. As for the suspect's description, police only know that he was wearing a black hooded sweatshirt.