The Hickory Police Department said the artificial left leg belonged to Zahra Baker, who lost her own leg to bone cancer. Police said the serial number on the leg recovered last Wednesday matched medical records that detectives collected from the girl's native Australia.
Police said a scanner was used to pull the serial number from a transponder inside the leg. Authorities released no other details, saying only that investigators continue to search the family's home in Hickory for additional evidence.
Zahra's father reported her missing Oct. 9. Authorities believe she is dead.
Searchers found the leg at a home where Zahra's stepmother once lived, Hickory Police Maj. Clyde Deal said last week. Deal said that the family lived at several locations in the county and that he wasn't sure how long ago they occupied that house. Authorities have said that the stepmother, Elisa Baker, is cooperating with the investigation.
Elisa Baker, 42, has been jailed on an obstruction of justice charge since the weekend Zahra disappeared. Police said she admitted to writing a bogus ransom note found at the scene of a fire in the family's backyard on the day her stepdaughter was reported missing.
Adam and Elisa Baker told police they had last seen Zahra in her bed at their home in Hickory, about 50 miles northwest of Charlotte. But police don't believe them.