BANGKOK - THAI authorities have arrested a tattoo artist suspected of killing a German tourist on an island popular among Western backpackers, police said on Monday.

Tiwat Kasempok, who owns a tattoo parlour, confessed to strangling 45-year-old Astrid Al-Assaad-Schachner on Saturday night on Pha-ngan island, said Police Colonel Jaroon U-chupap.

According to police, Tiwat said he had known the victim for more than a year and said she had had been stalking him and had accused him of trying to rape her. Tiwat was in police custody and could not be contacted.

Ms Al-Assaad-Schachner was a regular visitor to Thailand last year, sometimes staying for several weeks to join in the monthly parties to celebrate the arrival of the full moon.

Each month the 24-hour beach parties, known for their wild mixture of drink and drugs, attract as many as 10,000 revellers and are nearly always followed by reports of criminal activity, ranging from theft and drug abuse to rape and murder.

Ms Al-Assaad-Schachner, 46, was discovered on Sunday morning on Pha Ngan island, famous among tourists for its raucous full moon parties, said Lieutenant Colonel Somsak Nhurod of the local police station.

'There were some bruises on her left cheek and right hands, but those marks are not likely the cause of death. There was also no sign of rape,' Lt Col Somsak said.

'We suspect she might have been murdered somewhere else because her top half was naked but there were no signs of fighting at the spot her body was found or of her clothes,' he added.

The woman's body was being sent to Bangkok for forensic tests, he said. Her identity was not immediately confirmed.

The woman had come to Pha Ngan last month to take a course in tattoo art, Col Somsak said, adding that she was last seen at a party on Saturday night.

The German embassy in Bangkok was not available to comment.

Despite its reputation as a holiday paradise, Thailand has seen a series of tourist murders in recent years, including the shooting deaths of two Russian women whose bodies were found slumped on deck chairs in Pattaya in 2007. -- AFP, REUTERS