Young Laylah Peterson was killed Thursday when a shooter opened fire from outside the family's home. A dozen bullets went through the wall and one struck the girl in the head, police said.
"They have some leads, but that's about all we know," Laylah's aunt Tracy Martinez told ABC News.
She said the family is struggling to cope with the girl's murder.
"It's been really, really hard. We're trying," Martinez said. "It's a lot to process. Wednesday is the funeral. No one should have to bury a granddaughter or daughter at 5 years old."
Laylah was sitting on her grandpa's lap on the couch when she was struck by the bullet. Lt. Mark Stanmeyer said today that police are working to identify suspects and urged the public to call if they have tips.
Police have said they don't think anyone in the home was being targeted, and the house may have been mistakenly attacked.
The family donated Laylah's heart to save another child's life.
"She is going to be in our hearts, like her little baby heart is going to be in somebody else's," Police Chief Edward Flynn said during a news conference on Saturday with the girl's family, according to The Associated Press. "We know that as awful as this event has been, she is going to live on and save a life."
Police "are not going to rest until we find the perpetrators of this vicious crime to justice," Flynn added.
Martinez described Smith as a "quirky, loving" little girl who loved dressing up like a princess and singing her favorite songs, "Let It Go" and "Jesus Loves the Little Children."