Cambodian police have said they fear missing British backpacker Amelia Bambridge has drowned.
The 21-year-old, from Worthing, West Sussex, was last seen on the island of Koh Rong late on October 23.
She was reported missing after she failed to check out of her hotel on time and staff at Police Beach, a private venue on the island, found her purple rucksack with her purse, phone and bank cards inside the following morning.
Members of Ms Bambridge’s family have travelled to the island to join the search.
On Wednesday, the police chief for Preah Sihanouk province, the area where Ms Bambridge was last seen, said he believed she has drowned.
Major General Chuon Narin said searches of Koh Rong island and in the Gulf of Thailand had failed to provide any information about her disappearance.
However, he said land and sea searches will continue until she is found.
About 150 volunteers including divers, navy personnel and visitors as well as Cambodian police are involved in the hunt.
It is understood that the Foreign and Commonwealth Office (FCO) has had members of staff on the island for a number of days.
Six men who work at restaurants, hotels and guest houses on the island were questioned and released without charge on Tuesday evening.
Officials said the men were taken into custody because of complaints by Western tourists that they had acted badly towards visiting women.
On Wednesday, Ms Bambridge’s family criticised the Foreign Office for its lack of support in a petition.
The change.org petition was started by Ms Bambridge’s close friend, Temisis Conway, and has been promoted by members of the missing backpacker’s family, including her sister, Sharon Schultes.
The petition said the FCO is not helping them look for Ms Bambridge.
The post said: “We have had no support from our own UK Parliament and currently have been without a good translator for days now.
“This is proving difficult to transfer information to the family and we fear this could hinder our chances of safely bringing her home.
“It is the duty of the Foreign and Commonwealth Office to stand up for British people in need, wherever they are in the world, and as of yet they’ve not done anything of the sort.”
An FCO spokesperson said: “Amelia’s family have our deepest sympathies at this very difficult time. Our staff have been providing in-person assistance to them on Koh Rong island, and maintaining close contact with the Cambodian authorities searching for Amelia.”
Ms Bambridge set off on her trip on September 27, when she flew to Vietnam, her family said.
Her father, Phil Bambridge, who has travelled to the island, said on Tuesday that he believed she had been “taken”.
Mr Bambridge added that, having viewed CCTV, he believed she had been lost inland.
A fundraiser launched by Ms Schultes to cover the search has raised more than £16,000 since Friday.
She said on the page: “No retreat, no surrender, we are gonna find her.”
Five relatives are now on the island and drones and thermal imaging cameras are assisting with the search.
A vigil for Ms Bambridge will be held at St Michael’s Church in Worthing on Wednesday evening.