Police searching for a British teenager missing in Malaysia are to play loudspeaker recordings of her family in a bid to find her.
Detectives believe Nora Quoirin, who has learning difficulties, may be lost in the jungle and will move towards the familiar sound.
The youngster, 15, vanished from the Dusun Tropical Rainforest Resort, where her family were staying, on Sunday.
Her parents raised the alarm when they found her bedroom empty that morning and the window open.
Meabh and Sebastian Quoirin, who live in London, say they fear she has been abducted.
But police are continuing to focus their enquiries around the theory she may have left the resort of her own accord and could now be stranded in a small 2.5 square mile area of the surrounding rainforest in Negeri Sembilan state.
The force has analysed fingerprints found in a resort cottage from which Nora was reported missing, despite previously saying there were no initial signs of foul play.
Speaking on Thursday, district police chief Mohamad Nor Marzukee Besar said officers would “be using a loudhailer to call her” and revealed her parents had been interviewed to “find out what voice the victim would like to hear”.
He added: “We hope that on this fifth day we will be successful in finding the missing victim.”
Some 200 officers, along with indigenous trackers, have been divided into six teams for the ongoing search.
The family's statement said: “We would like to thank our embassies, the local community, and the staff here at the hotel and anyone else who has offered help to find Nora.
“We also welcome the assistance of the French, British and Irish police.
“We are completely overwhelmed by the support we have received from all over the world.”
While the family themselves released a statement thanking authorities for the efforts, Nora’s grandfather Sylvain Quoirin suggested there were concerns the right line of investigation was not being pursued.
“In my opinion, the adventure escapade line of inquiry is not at all valid,” he told the BBC, adding the schoolgirl was “very shy, very reserved, very fearful”.
A statement released by the Lucie Blackman Trust, a charity which helps families of those missing overseas, said: “This is extremely traumatic.”
An online fundraising page set up for the family had raised more than £55,000 by Thursday morning.
