A manhunt was under way for a backpacker suspected of murdering a British man and a woman found semi-naked on a beautiful Thai beach, according to reports.
The suspect may have fled to Bangkok from the divers' paradise island of Koh Toa, where David Miller, 24, from Jersey, and Hannah Witheridge, aged 23, from Great Yarmouth, Norfolk, were battered to death.
A blood-stained hoe, believed to be the murder weapon, was found nearby.
Locals were reported to have blockaded Koh Tao's only pier to prevent the killer escaping.
According to the Daily Telegraph, local police chief Colonel Songsak said a British man who may have known the male victim had left the island.
His name has been circulated to police but not given to the media.
The British authorities were aware of reports about the suspect and a source said they were "looking into them urgently".
It was not thought the victims were a couple, but had met recently on the island.
Their bodies were found on a rocky section of the shore around 100m from the scene of a beach party.
Police Colonel Prachum Ruangthong said: "The man was chopped in the back and on the side of his head, while the woman was chopped in her face.
"It's very gruesome."
Investigators were checking CCTV from local bars and restaurants at the usually-peaceful destination, known for its turquoise seas.
Its bright coral, sharks and rays bring in divers, hikers enjoy jungle walks and the bar scene "rages on until dawn", according to the Lonely Planet travel guide.
The horrific murders could badly damage tourism in Thailand which has already been affected by the country's deep political crisis and the introduction of martial law.
States of Jersey Police said family liaison officers were working with the family and close relatives of the dead man.
But a spokeswoman for the force said it was not in a position to name the victim, who may not have been formally identified, as that was up to the Thai police.
A Foreign Office spokesman said: "We are aware of the death of two British nationals on 15 September on the island of Koh Tao in the Gulf of Thailand. The Embassy are urgently seeking information from the local authorities and Consular staff stand ready to provide assistance to friends and family at this tragic time.
"The Consul from Bangkok is travelling to Koh Tao as soon as possible."