"The past week has been a horrific experience and clearly multiple mistakes have been made," Dolores Renta said.
The money Guerra's friends raised at a car wash over the weekend will now be split. Some will go towards Cantu's burial and the rest to Guerra's medical expenses.
Guerra was taken to the hospital in critical condition with a brain injury, broken back and a collapsed lung.
"We are still in shock," said Guerra's cousin, Michelle Cisneros. "This is not something we ever expected, as well as the other family too."
There was a similar mix-up four years ago in Indiana where officials confused who lived and who died after a car crash involving two women. Since then, Indiana passed a law requiring stricter identification of the deceased.
In Phoenix, Guerra's family said they hope the mistake will never happen again.
"Everyone identified," said Guerra's aunt, Dorenda Cisneros. "Everyone came in and said that's who it was and there's really no good excuse."
