Police in Thailand investigating the rape and murder of 21-year-old Welsh tourist Katherine Horton say they are close to making an arrest.
Katherine Horton was last seen phoning her mother on 1 January
A British couple found her mobile phone abandoned on a beach and have provided vital clues, said police.
The body of Miss Horton, a Reading University student from Cardiff, was flown back to the UK on Saturday, five days after she was found in the water.
Police said they had a list of suspects and could make an arrest in days.
Reports have suggested that the British couple, who were also on holiday on the island of Koh Samui, saw Katherine pass by them as they took an evening stroll on the night of 1 January.
They later found her phone in the sand.
A Thai police spokesman said: "We have enough detail to start searching suspects and next week maybe we can apply for arrest warrants."
More than 100 Thai officers have been working on the case since Prime Minister Thaksin Shinawatra ordered police to trace the killer.
The Thai prime minister ordered police to trace the murderer
The prime minister has now been quoted as saying that police have clues to identify those responsible.
The Foreign Office said on Sunday however that it was unable to confirm any developments in the investigation.
Miss Horton, a final year psychology student who was on holiday with her university friend Ruth Adams, went missing after wandering onto a beach to speak by phone to her mother Elizabeth.
The Bangkok Post reported Maj-Gen Assawin Kwanmuang, deputy commissioner of the Central Investigation Bureau, as saying that telephone records showed Miss Horton made her last call to her mother between 2143 GMT and 2200 GMT on New Year's Day.
Miss Horton's body was discovered on the shoreline the following day.
Police said tests showed she had been raped, beaten and then drowned.
On Saturday police told a press conference that two different DNA samples had been recovered from her body.
Tests are reported to have shown that the DNA was from Asian men and police have been testing a number of Thais in a bid to match the samples.
Miss Horton's father, Ian, and brother, Christopher, flew to Thailand and made an appeal for help to find the killer. They have now returned to the UK.
A post-mortem examination has already been held in Thailand, and a second one is due to be carried out in Britain in the next few days.
An inquest will also be held in Cardiff.