(CNN) -- Zahra Baker had been an international symbol of strength and hope: A freckle-faced girl who lost part of her left leg at age 5 and her hearing while being treated for cancer, she kept smiling and fighting through it all.
Yet Zahra's life ended violently in fall 2010. That's when her stepmother, Elisa Baker, told police in Hickory, North Carolina, that the girl, then 10, was killed and dismembered, according to search warrants. The youngster's body parts were then disposed of in various locations, the stepmother told police.
While police found some of Zahra's remains in the weeks after she was reported missing, some parts hadn't been accounted for. But authorities took a major step forward on this count Thursday, with the confirmation that a skull found in April 2012 in Caldwell County, North Carolina, belonged to the girl.
"The life and death of Zahra Baker profoundly impacted those who came to know this brave young lady through her tragic story," said District Attorney James Gaither Jr., whose district includes the section of central North Carolina where the crime occurred and whose office confirmed the finding about Zahra's skull.
"Zahra and her life will be forever in our thoughts, and 'Team Zahra' will forever be connected through her spirit."
Members of the North Carolina State Bureau of Investigation, the North Carolina Medical Examiner's Office and the Marshall University Forensic Science Center in Huntington, West Virginia, analyzed the skull and told Gaither's office it belonged to Zahra. But the analysis did not establish the cause of the girl's death.
Police began looking for Zahra on October 9, 2010, after her stepmother reported her missing and authorities found a ransom note that was later determined to be fake. At the time, authorities said that no one other than a relative had seen the girl since September 25.
Elisa Baker was arrested the next day on several charges unrelated to Zahra's disappearance, including writing worthless checks.
Meanwhile, the search for the young girl grabbed national and international headlines given her story, her age and the fact both of her biological parents are from Australia.
A prosthetic leg thought to belong to the missing girl was found in a brushy area off a North Carolina road in late October 2010. Some of her other remains were found November 11 of that year.
Zahra's stepmother eventually told police the girl had been killed two weeks before she was reported missing.
In September 2011, she pleaded guilty to second-degree murder with aggravating factors and was sentenced to 18 years in state prison, according to the district attorney's office.
According to an indictment, Elisa Baker "desecrated the victim's body to hinder detection, investigation and prosecution of the offense."
She is now in federal custody awaiting sentencing on drug conspiracy charges after pleading guilty in January 2012 to one count of conspiracy to sell drugs.