Some of murdered Milly Dowler's bones were scattered over a wood by wild animals, the Old Bailey has heard.
Pathologist Hugh White said the schoolgirl had probably been in the wood in Yateley, Hampshire, for "months not weeks". But there was nothing on the bones to suggest how she died.
Milly, 13, who disappeared six months earlier, was initially identified through her dental records and an old shoulder fracture.
Dr White said he was taken in September 2002 to a 100-yard long site to view "scattered human bones on the ground, some gnawed by animals".
He said: "The remains were incomplete because of animal activity but there was no other obvious cause of injury."
He could not exclude suffocation or strangulation but was unable to say what had caused her death.
Asked if he could exclude natural causes, Dr White said: "Yes. This is a girl of 13 years old found in an environment where she could not have got to by herself - and she was without any clothes."
Milly vanished on March 21, 2002, in Station Avenue, Walton-on-Thames, Surrey, as she was walking home from school. The prosecution allege convicted killer Levi Bellfield, who was living in a flat there, abducted and killed her before dumping her body 25 miles away.
Bellfield, 43, denies abducting and murdering Milly, and attempting to kidnap 11-year-old Rachel Cowles, the day before.
Bellfield, a former wheelclamper and bouncer, was convicted in 2008 of the murders of Marsha McDonnell, 19, and Amelie Delagrange, 22, and the attempted murder of Kate Sheedy, 18.