The trial of the fishermen ended Wednesday just 17 days after the rape and murder of 21-year-old Katherine Horton on the resort island of Samui.

Prime Minister Thaksin Shinawatra had made an unusual public call for the two men to face the death penalty, saying the crime had damaged Thailand's vital tourism industry, which is still rebuilding after the tsunami in 2004.

The breakneck speed of the investigation and conviction of the two men, who confessed they killed the student after drinking and watching pornographic films, drew criticism from human rights watchdog Amnesty International.

"Amnesty International opposes the death penalty in all cases, but the added concern in this high-profile case is the speedy manner in which the trial was held and that the suspects may not have had time to mount an adequate defence," said T. Kumar, the group's advocacy director in Washington.

But Tanes Petsuwan, a spokesman for the Tourism Authority of Thailand, said he hoped the quick trial would send a positive message to tourists about the country's commitment to security.

"After the case happened, there was much action from the level of the Thai prime minister, ordering immediately national police and local police to try to close this case, which I think the police did it quite well," Tanes said.

Police defended themselves against the criticism, saying DNA evidence and convincing witnesses gave them a clear-cut case.

"Resolving this case swiftly will boost our country's image," national police spokesman Ajiravid Subanbhesaj said.

Police also said Thursday that they plan to increase patrols on Samui, adding 15 officers to the tourist police force, and would tighten regulations on fishing boats.

John Koldowski, who analyses tourism trends for the Bangkok-based Pacific Asia Travel Association, said the government had moved quickly to control any damage the crime caused to Thailand's image.

"You can see that they're extremely concerned about the negative image this could generate overseas," he said.

So far, tourism authorities have recorded no cancellations since the murder and the government still expects arrivals to Samui to increase about five percent to more than one million people this year.

Tourism accounts for six percent of Thailand's gross domestic product, and memories of the devastating December 2004 tsunami which killed nearly 5,400 people in the country still linger.

"It's the last thing you want to have -- this series of events, either natural or man-made, with a very dark underside," said Koldowski.

Despite the tsunami, overall tourism in Thailand has remained strong. Although arrivals fell short of the government's target, the number of foreign visitors rose 10 percent last year to some 12.1 million people.

While Thailand bills itself as the "Land of Smiles" with sunny beaches, there are regular incidents of foreigners involved in sexual assaults, drug offenses and sometimes rape or murder.

Britain's Foreign Office says nine of its nationals have been murdered in Thailand since August 2004, and urges women to exercise caution amid regular reports of sexual violence against men and women.

A 57-year-old British man was beaten to death at Christmas in his bungalow in Koh Chang, southeastern Thailand. Just last weekend a 29-year-old woman was raped in the beach resort of Pattaya, southeast of Bangkok.

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