Police Sunday confirmed the mobile phone of Koh Tao murder victim David Miller had been retrieved from the accommodation of one of the two Myanmar suspects.
National police chief Somyot Pumpanmuang said suspect Zaw Rim, 21, had intended to take the victim's mobile phone for his own use, but he later found the device cannot be used in Thailand, so he smashed and discarded it in his living quarters.
Pol Col Prachum Ruangthong, superintendent of the Koh Phangan police station, said the device is a black iPhone 4, taken from the shorts pocket of Miller, 24, who was found dead on a Koh Tao beach alongside Hannah Witheridge, 23, on Sept 15.
The confirmation came as doubts spread on social media as to whether the phone was really taken from the suspects. Some pictures circulated online show a friend of Witheridge brought a mobile phone to Pol Col Prachum during the inquest.
Critics, especially those in the British press, have accused Thai authorities of bungling the probe by chasing the wrong leads. There have also been concerns the suspects are scapegoats, a claim Prime Minister Gen Prayut Chan-o-cha denied.
Zaw Rim and Win, both 21, have been detained in Samui prison since Saturday. Both Myanmar workers were charged with premeditated murder, rape, theft and illegal entry into Thailand.
Police said the suspects earlier admitted they had raped and killed Witheridge after they watched her and Miller, who was also killed on Sept 15, hugging and kissing.
Acting Assistant National Police Chief Pol Lt Gen Panya Mamen said police have strong forensic proof to back their case against the suspects.
The two are the culprits, not scapegoats, he said, adding that evidence in the investigation documents is confidential and disclosing it could affect the probe.
Meanwhile, Pol Col Prachum said the Koh Tao police operation centre, which was earlier set up to unravel the murder case, has been moved to Bophut police station in Koh Samui.
Eight investigators are now finishing the probe document before sending it to prosecutors, he said.
Pol Col Prachum said police will not question the suspects any more as the interrogation is complete.
The DNA test results will be compiled in the probe document, which will be sought for the pair's indictment, he added.
Meanwhile, tourism on Koh Tao shows signs of returning to normal as many foreign travellers have come back to the island.
Tourism operators there said tourist activity has apparently picked up since police succeeded in unraveling the murder case and apprehended the suspects.