PHOENIX - Police are looking for the driver of a blue or silver early-2000s Nissan Altima after a hit-and-run crash killed a 6-year-old girl and sent her mother to the hospital with serious injuries Saturday night.

Melissa Cabrera -- better known by her middle name, Briana -- tried to cross the street with her mother after a school function at St. Louis the King School on Maryland and 43rd avenues.

They didn’t know it would be their final moments.

"It’s really tough,” said Iris Amador, reduced to tears talking about the loss of her niece. “It happened way too soon.”

The fatal hit-and-run crash happened in front of classmates, teachers and other faculty.

"Briana and her mom, Zara, had a wonderful day Saturday evening,” said Charlene Krushinsky, M.Ed., the principal at the Catholic school. “As everyone was starting to go home, [that] is when the accident occurred."

Phoenix police said neither one was in the crosswalk. They also said they don’t believe speeding was an issue.

But the driver at fault is nowhere to be found.

Krushinsky took the lead on planning a funeral for Cabrera since Cabrera's mother, Zara Amador, is still in the hospital with four fractures in one arm, as well as a leg and foot injury.

“She’s [emotionally] destroyed,” said Amador about her sister. “That’s her little girl.”

She was a little girl who had so much love to give and so much to look forward to.

“She was a very happy girl,” Amador said. “You’d arrive and she would hug you and give you a kiss … She wanted her own quinceañera party one day."

Now, the only thing that the family wants her for the first-grader who died too young is justice.

"There are no words to explain everything we feel right now," Amador said. "I want the person responsible to pay for what they did. It’s so hard. [She was] a 6-year-old little girl."

Krushinsky said a local funeral home is charging only half its normal fees for funeral-related expenses.

But they still need to raise $5,000.

If you’d like to help, you can donate to the Briana Cabrera Memorial Fund at any Wells Fargo Bank location. The account number is 8153361863.

You can also leave a check made out to “Briana Cabrera Memorial Fund" at the St. Louis the King School.