Two British backpackers were shot dead by an off-duty Thai policeman near the site made famous by the film The Bridge on the River Kwai.
In the early hours of yesterday, the couple - Vanessa Arscott, 23, and Adam Lloyd, 25 - got into an argument at the S&S restaurant, a small riverside eating place near Kanchanaburi, 80 miles north-west of Bangkok, Thai police said.
The couple were the only foreigners in the patio beer garden when Mr Lloyd grew angry with people staring at his girlfriend, according to a police source. Police Major Chavalit Piakaew said: "The male tourist was apparently upset by the way other people in the shop looked at his girlfriend and his jealousy got out of control."
There were conflicting reports about how the incident unfolded but one police source said the restaurant owner, who is also a 39-year-old Thai police sergeant, got involved in an argument with the couple and approached them in his car after they left. He shot Mr Lloyd three times and then ran over Ms Arscott, dragging her body under his car for 20 yards. Seconds later he shot her twice at close range.
Major Piakaew said Mr Lloyd and Ms Arscott died on their way to the Phahol Polpayuhasena hospital and the gunman escaped.
Police Colonel Vej Somboon said an arrest warrant was issued for Sergeant Somchai Wisetsingha, a joint owner of the restaurant, whose private car was found with bloodstains and who has been missing since the shootings. "The witnesses and evidence show that he is the man who gunned down the British tourists," Col Somboon said.
The British embassy's acting consul, Fiona Borisuth, and other officials arrived at the town, collecting the couple's passports and personal belongings from the Sugar Cane 2 guest house.
Ms Arscott's mother and father, Joyce and Graham, and her sister, Alyssa, were being comforted last night by friends and relatives at the family home in Ashburton, Devon. They said in a statement: "Vanessa was a joy in our family, both beautiful and vivacious, and about to embrace life's big adventure with both hands. She had met her boyfriend Adam, and together they had a strong and lovingly supportive bond and were planning to live their lives as a couple. Our family's heart goes out to Lynne and Brian, Adam's parents."
Ms Arscott's grandmother Eileen Arscott, who lives in nearby Kingsteignton, said the pair had travelled to Thailand on 3 July and they were due to return home this weekend.
Adam Lloyd originally came from Northampton but he and his parents recently moved to run the Buckingham Lodge Hotel in Torquay. He had three brothers. Mrs Lloyd said: "I just can't believe it. They just went off on holiday together as a happy couple and now we hear this dreadful news. He and Vanessa had been travelling together for two months. It was something he always wanted to do. They were due to come back this Saturday."
There have been several murders of foreign tourists in Thailand including that of 23-year-old Kirsty Jones from Brecon, south Wales, who was murdered in a guesthouse in Chiang Mai in August 2000. Last month, a Scottish backpacker Mark Lemetti, 24, was beaten to death in southern Thailand. Violent crime rarely affects visitors to Kanchanaburi, but last year a French tourist was shot by a robber on a motorbike while walking to his guesthouse with friends.
The railway and bridge, immortalised in David Lean's 1957 film The Bridge on the River Kwai, were built by 61,000 Allied PoWs and 250,000 Asian labourers working in the most appalling conditions. The line became known as the Death Railway after about 100,000 Asians and 16,000 Allies lost their lives in its construction.