Police said they arrested him after employees of a resort on the beach told police that the suspect was seen strolling near the scene where the two British tourists were killed on the night of September 14.
Besides they also found a significant evidence which is a blood stain on his clothes.
Police said the suspect urgently left the popular diving paradise on the first ferry to the mainland the next day after the murder was discovered.
But the police said they are awaiting DNA test to prove the blood stain, and also from DNA samples tested by the Police Forensic Office if any DNA sample matching DNA found at the scene and the victim’s body.
Police have collected DNA samples from suspected foreign workers who lived near the scene for test.
Two Britons were discovered nakedly on a blood-stained beach on Koh Tao island last Sunday with deep wounds to the head and face.
The pair were attacked with a blood-stained hoe found with their clothes and suspect British girl had been raped.
The victims were at a beach party on Sai Ree Beach with about 50 other international revellers.
One resort employee said the bodies were found behind large rocks near the bungalows where they were staying.
‘It was the first time this has happened on the island, I have never seen anything like this,’ she said.
Tourist Police Division commander Pol Maj-Gen Apichai Ti-amnart disclosed Wednesday that three Myanmar workers, who were earlier detained for question after being suspected, have been freed after interrogation showed they were not involved.
He also said tourist police yesterday escorted and seen off three British female tourists who came together in the same group with British girl at Suvarnabhumi airport Tuesday night back to London.
They were still shocked with the murder, he said.
The British girl from Great Yarmouth, Norfolk, was with four friends and arrived Wednesday September 10 on the island where she met the man, who had been there since August 25.
Forensic police chief Pol Maj Gen Pornchai Suthirakun said Wednesday morning that doctors would conduct autopsy on the two Britons’ bodies today to compare with DNA samples collected from suspects.
The result would be known in the afternoon.
The bodies of the two Britons arrived at the Police General Hospital yesterday.
They were discovered half-naked on a blood-stained beach on Koh Tao island with deep wounds to the head and face.