Zahra Baker was murdered and then dismembered, but an autopsy on the 10-year-old Australian girl's remains failed to determine exactly how she was killed.
"Based on the history and autopsy findings, it is our opinion that the cause of death in this case is undetermined homicidal violence," the autopsy report by the North Carolina Medical Examiner states.
The report was released hours after District Attorney Jay Gaither announced a grand jury in North Carolina had charged Zahra's US stepmother, Elisa Baker, with second-degree murder.
Baker, 42, faces eight to 30 years in jail if convicted of Zahra's murder.
Zahra's biological father Adam Baker has not been charged and Mr Gaither said there was "no credible evidence to suggest that anyone other than Elisa Baker was involved in the murder of Zahra Baker".
Zahra's skull, right arm, right leg, left forearm and hand remain missing.
The autopsy report does offer hints about the dismemberment and disposal of parts of Zahra's body in bushland around her adopted hometown of Hickory, North Carolina.
Bones found by authorities had "distinct cut marks", the autopsy report states.
"Several of the bones exhibit cutting tool marks that are consistent with dismemberment," according to the autopsy report.
"The marks grossly appear to result from the use of at least two different cutting instruments."
The cut marks on the bones "indicate that the decedent was dismembered and are presumed to have occurred postmortem".
The report also describes how "multiple allegations of abuse" on Zahra "were reported to Department of Social Services during 2010".
Zahra was last seen alive on September 24, 2010, but was only reported missing by her father on October 9.
She moved from Queensland to the US with her father in late 2008 to be with Elisa Baker.
Zahra had to have her leg amputated above the knee in 2005 after a battle with bone cancer.
