The search continues for the killer of two British tourists in Thailand. Results of DNA tests have shown that there was no match between crime scene DNA and the DNA of British backpackers who were questioned over the murders. David Miller and Hannah Witheridge were found dead on a beach on the island of Koh Tao on Monday. Police reportedly took DNA samples from 12 potential suspects this week, including two other British backpackers. All 12 have now been cleared of the murder, according to reports. A post-mortem carried out on 23-year-old Hannah Witheridge and 24-year-old David Miller, shows that the young woman died from severe head wounds. Mr. Miller is believed to have suffered head injuries and then drowned in the ocean. It has also been reported that he had wounds on his hands, indicating possible signs of a struggle. The bodies of the two victims were found near the location of where a beach party had taken place on Sunday night. Police stated that a blood-stained hoe was found near the bodies which officers suspect is the murder weapon. The police have followed a number of lines of investigation over the past few days, which includes interviewing migrant workers, other British tourists and they also released CCTV footage of the lead-up to the attack. According to reports, police now believe that there may have been more than one attacker. The BBC has reported that the investigation has ran into a number of problems because the crime scene was not sealed off and people were not stopped leaving the island after the killings. Members of Miss Witheridge's family are said to be arriving in the Thai capital of Bangkok. In a statement following the death of Miss Witheridge, who is from Great Yarmouth in Norfolk, the family said: “She was selfless and caring and made each and every day that little bit more wonderful.” Family of Mr. Miller, from Jersey, stated; “David was an artist by temperament. So talented…he was hard-working, bright and conscientious, with everything to look forward to. “David was very giving to his family and friends and we all adored him. He will be sorely, sorely missed.” Meanwhile, Thai general Prayuth Chan-ocha has sparked outrage by appearing to suggest that tourists couldn’t believe they are safe in Thailand if they choose to wear bikinis. “There are always problems with tourist safey,” he said. “They think our country is beautiful and is safe so they can do whatever they want, they can wear bikinis and walk everywhere. “Can they be safe in bikinis…unless they are not beautiful?” he said amidst massive public outcry.