Two British men are being questioned by police over the murder of a couple in Koh Tao.
The men, who spent time with the victims in the days before they died, are now in ‘police care’ in Bangkok.
According to the latest BBC report, the men, believed to be brothers, were stopped at Bangkok International Airport as they prepared to leave the country.
Police said they had not been formally detained or arrested but were being questioned again following new forensic evidence.
One of them had already been questioned on Monday shortly after the bodies were found, but was later released.
The other man had already left the island.
Police had previously switched their suspicions to the island’s immigrant worker community.
Six Burmese nationals arrested after raids on Tuesday remain in police custody and have undergone DNA testing.
The bodies of Hannah Witheridge, 23, from Great Yarmouth, and 24-year-old David Miller from Jersey were found on a beach in the early hours of Monday morning.
Since the grim discovery, the island, close to Koh Samui, has halted ferry services and closed its port to try to stop the killer or killers of the two backpackers escaping.
A TAT spokeswoman said: "We understand this to be an isolated incident and is very much out of character for an island which is much loved for its quaint atmosphere.
"Local authorities have begun a thorough investigation and have put restrictions in place for the time being to prevent anyone leaving the island.
"This may have an impact on tourists’ travel plans so we suggest they contact their travel agent, tour operator or chosen hotel for further advice if they are currently on, or are due to travel, to the island in the next few days.
"Our thoughts and condolences are with the families and friends affected by the news."
It is believed that Hannah and David did not know each other when they first arrived in Koh Tao separately at the end of August but could have become friends later on.
They met while staying at the same hotel, where they also become friends with a third British traveller, and all three arranged to go out together on Sunday night, according to the local officers.
The bodies of the pair were found hacked to death, hidden behind rocks, and a blood stained hoe was found nearby.
TAT said that while Koh Tao was not on the main tourist trail, it was popular with backpackers and those with a keen interest in snorkelling and diving.
It added: "Koh Tao, and other beach and island destinations across Thailand, remain safe for tourists to travel to."
Hannah’s father, Tony Witheridge, runs Carefree Holidays, which runs self-catering parks in Hemsby, Newport and Winterton on Sea near Great Yarmouth and the Norfolk Broads.
