Surapak Phuchaisaeng was arrested in Bangkok on Friday, said a senior police officer at the Technology Crime Suppression Division.
Under Thailand’s controversial lese majeste legislation, anybody convicted of insulting the King, Queen, Heir or Regent faces up to 15 years in prison on each count.
Surapak, who also faces related charges under the Computer Crime Act, is one of the first people arrested for insulting the monarchy since a new government took power last month.
Prime Minister Yingluck Shinawatra said after her July 3 election win that the rules should not be misused, following several high-profile cases against supporters of her brother Thaksin, fugitive former leader.
But in a sign she did not want a direct confrontation with the country’s powerful elites, her government has since vowed to set up a “war room” to crack down on alleged online royal insults.
Earlier this month more than 100 international academics called on Thailand to review the tough laws, saying political abuse of the legislation is undermining human rights.
The laws have come under heavy criticism from rights groups, which have expressed concern that they have been used to suppress freedom of expression under the last government, considered close to the establishment.
In March, a webmaster was jailed for 13 years after the Internet site he ran, linked to the opposition movement, allegedly published comments insulting the monarchy.
Another website editor currently on trial faces decades in prison if convicted – for failing to remove reader comments quickly enough.
Discussion of the royal family’s role is a long-standing taboo in politically-divided Thailand.
Meanwhile a US citizen who says he risks prison in Thailand has sued an Internet company for allegedly handing over his personal data, in a legal test touching on the kingdom’s tough ban on royal insults.
Anthony Chai, a Thai-born naturalised American who runs a computer store in California, said in a lawsuit that Canadian web service provider Netfirms.com Inc broke US law by sharing his personal information with Thai authorities.
On a now defunct website, Chai posted anonymous comments critical of Thailand’s lese majeste law.
Even though he did not identify himself on the site, Chai said that agents pulled him aside for interrogation at Bangkok’s airport and that he fears imprisonment if he returns.
In comments to AFP, Chai said he hoped to draw attention to the “despicable” law on lese majeste and to test Thai authorities’ contention that their rules apply around the world and not only inside the kingdom.
“So many innocent Thai people are now rotting in jails across the country in Thailand because of their belief in freedom of expression,” Chai said.
Such expression “does not contain any violence or promotion of violence. The whole country is held hostage by this law,” he said. – AFP