The mother of Nora Quoirin has said evidence may have been lost because police were slow to act on the possibility her daughter could have been abducted.
The Irish teenager's body was found near a Malaysian jungle resort where she vanished while on holiday with her family last year.
Meabh Quoirin told an inquest into her daughter's death she believed she heard "muffled whispering" inside the family's cottage the morning Nora disappeared, but she took no action because she was not fully awake at the time.
Ms Quoirin, who is from Belfast, said police were more focused on search and rescue and only started looking for fingerprints and interviewing resort staff several days later.
She said the police officer sent to take her statement also struggled to communicate in English and she had to explain herself repeatedly.
Some senior police officials who later approached her were "quite rude and arrogant", she said.
"My own understanding was that the dominant commitment was in search and rescue, and it took a long time to mobilise and explore any criminal route," she told the inquest via video-link from her London home yesterday.
"I believe that criminal evidence, if it existed, would have been lost during that time."
Nora's disappearance the day after the family arrived at the Dusun eco-resort on August 4 last year, sparked a massive search.
The 15-year-old's naked body was found on August 13 beside a stream about 2.5km from the resort.
Police have told the inquest an investigation showed no criminal element, and there was no indication Nora had been abducted.
Officers believe she climbed out of a window on her own, and the post-mortem examination showed she succumbed to intestinal bleeding due to starvation and stress.
But Ms Quoirin and her French husband, Sebastien Quoirin, say they believe Nora was kidnapped because she had disabilities and could not have wandered off on her own.
Ms Quoirin broke down at one point during her four hours of evidence at the inquest.
She said it would have been almost impossible for her daughter to push open and climb out of a window with her limited strength. The window could not be locked because the latch was broken.
The children were sleeping in the loft, while she and her husband were downstairs, Ms Quoirin said.
She also said that her younger daughter woke up to go to the toilet and noticed Nora was missing, but thought she had gone to sleep with her parents.
Ms Quoirin said that at one point during the night she "was aware of muffled sounds inside", like two people whispering.
"I was in between sleeping and being awake, so I wasn't really processing my thoughts. It caused me no alarm because I wasn't fully conscious."
She said Nora would not necessarily have cried for help because she was "highly submissive", which could prove why there were no marks of struggle on her body.
"She would just be silent and stare at the floor and close in on herself," she said.
Ms Quoirin noted that the area where Nora was found had been repeatedly searched, and that given the steep and hilly terrain, her body had only minor bruises and scratches.
"Why does her state of body not reflect that of someone constantly moving or exposed to the harshest of elements?
"I don't want to speculate on the motivation of the abduction," she said.
"It is possible and reasonable to believe that any plan that was conceived at any point may have to change by the sheer volume of attention focused on Nora's case.
"I believe that Nora could have subsequently been released by her captors."
Her husband is due to give evidence today.