Police in Pattaya have detained a Lithuanian man whose transgender girlfriend was found slain in a locked room at her house in Prasat district of Surin on Wednesday.
Marius Kunickas was tracked down using the signal from a mobile phone he allegedly took from his dead lover. He is believed to be about 30 years old.
The suspect was being taken back to the lower northeastern province for DNA testing. If his sample matches evidence found at the scene, he will be arrested and charged with murder, according to media reports.
The body of Thiraphong Lamluea, 31, was found at her two-storey house in tambon Kang-an around 4.30pm.
Pol Capt Sanee Chimngam, a duty officer, said the body was wrapped in a thick blanket. It is believed she had been dead for at least a week.
Thiraphong's mother, Wandee Lamluea, 47, said neighbours informed her of a nasty odour coming from her son's house. She called a local rescue team to inspect the property.
They found marks on the floor and traces of hair and bloodstains outside the door to a spare room. Inside Ms Wandee found her son, a transgender woman, lying dead under a blanket.
A pit bull terrier had also disappeared and she suspected it had been killed and buried somewhere.
Thiraphong was the eldest of Ms Wandee's three children and the breadwinner of the family. She had been romantically involved with Mr Kunickas, whom she met in Phuket, for 6-7 months.
Thiraphong had brought her lover to Prasat district twice, in January and late May, her mother said. During the first visit, they stayed at a hotel. On the second visit, they stayed at Thiraphong's house.
She said Mr Kunickas had stayed at the house for one week. On May 26, the man brought a box of beer to the house and they drank it together. Ms Wandee noticed what looked like bloodstains on his legs, and she also saw some bruises.
He claimed a bottle had broken and some fragments had hit his legs, Ms Wandee said. She had no reason to doubt him and they kept drinking together until about 9pm, when he left. However, Thiraphong had not joined them that evening.
Around 2am the next day, Ms Wandee went to the market passing Thiraphong's house. She did not see the car her son had rented and driven from Ubon Ratchathani province. She assumed the couple had left together.
According to Ms Wandee, police have surveillance camera footage showing the rented car at Prasat district bus terminal. Mr Kunickas was also seen boarding a bus to Rayong.
She said Thiraphong also had a British boyfriend. They had known each other for seven years. He lived in the UK and had not returned to Thailand for a long time. She suspected Mr Kunickas was jealous of him.
Ms Wandee said Thiraphong's head had been beaten and she believed the killer had used a bottle.