The teenager’s body was found beside a stream on Tuesday less than two miles from her accommodation in the Dusun rainforest resort.
A post-mortem examination revealed the 15-year-old died from internal bleeding probably caused by hunger and stress.
Her family ,who have strong family connections to Derry, said the test results gave “some information” but she died in “extremely complex circumstances”.
“We are still struggling to understand the events of the last 10 days,” they added in a statement.
Nora’s family thanked the Malaysian authorities for their ongoing support and cooperation as the criminal and missing persons investigations continue.
“We will be bringing Nora home where she will finally be laid to rest, close to her loving families in France and Ireland,” the statement said.
Nora died two or three days before she was found, Malaysian Police believe.Her unclothed body was found after a 10-day search in an area that had previously been searched by rescuers.
She was described by her family as vulnerable having been born with holoprosencephaly, a disorder which affects brain development.
Her Irish-French parents, Meabh and Sebastian, previously said they do not believe she would have wandered off alone and feared she had been abducted.
Malaysian Police said there was no suspicion Nora was the victim of foul play.