Video report by ITV News Correspondent Sejal Karia
Nora Quoirin starved and died of intestinal rupture, a post mortem examination has revealed.
It is thought the intestinal damage could have been caused by hunger and stress.
The 15-year-old's body was discovered on Tuesday, nine days after she disappeared from an eco-resort she was staying at with her family in Malaysia.
The forensic doctor who carried out the post mortem examination said he believed the schoolgirl had died six days after she went missing, and that there was no evidence she had been abducted or raped.
Nora, who was born with learning difficulties and whose family described her as "vulnerable" disappeared on the night of the August 3-4.
Her body was found on Tuesday beside a small stream about 1.6 miles from the resort of Dusun, where she had been on holiday with her parents and two siblings.
Nora's devastated family previously said their "hearts are broken" and paid tribute to her as "the truest, most precious girl".
Describing how the teenager had “truly touched the world” after her disappearance sparked a huge search operation involving around 350 people, her family said: “Nora is at the heart of our family.
"She is the truest, most precious girl and we love her infinitely.
“The cruelty of her being taken away is unbearable.
"Our hearts are broken.
“We will always love our Nora."
The statement added: “We would like to thank all the people that have been searching for Nora and trying their best to find her.
“We thank the local people here and those far and wide for their prayers and support at this time.
“Nora has brought people together, especially from France, Ireland, Britain and Malaysia, united in their love and support for her and her family.
“To all our friends and family at home, we can’t thank you enough for all your love.”
Search crews looking for the teenager had played her mother’s voice in the dense Malaysian forest near where she disappeared.
It was volunteer helpers who found the body.
Police had previously said Nora - who was born with the brain defect holoprosencephaly, which her family said meant she struggled with everyday tasks - was believed to have climbed out of her resort room window.