Alanna Gallagher's body was found a few hours after she disappeared July 1, wrapped in a trash bag and dumped on a street near her home in Saginaw, Texas. Tyler Holder, a neighbor who was 17 at the time, has been charged with her murder.
The autopsy report said Alanna's hair was wet and the condition of her hands and feet suggests she was underwater for some time, the Fort Worth Star-Telegram reported Wednesday. But the medical examiner said it could not be determined whether that was before or after death.
Semen was found on Alanna's body, suggesting she was sexually assaulted. She was wearing only a pink shirt and sneakers when her body was found, although other items of clothing were in the bag with the body.
Her killer placed four plastic bags over her head and fastened them with red tape, causing her to die from asphyxia, the report said.
Holder also faces a charge of attempted murder of a police officer during his arrest.