Details of lese majeste charges last week against two of the eight administrators who ran a Facebook page making fun of Prime Minister Prayut Chan-o-cha has raised concern among netizens over the state of online privacy in Thailand.
In addition to sedition and computer crime charges, Harit Mahaton and Natthika Worathaiyawich were accused of insulting the monarchy based on personal messages in Facebook's chat function or standalone Messenger app.
The same goes for Burin Intin, a member of the Resistant Citizen group, who was arrested on the same charges on Thursday.
All three were denied bail.
The initial explanation netizens came up with was that it was possible their phones were always online and already connected to Facebook. When they were seized, officials can readily access it.
But later reports suggested this might not be the case.
Mr Narit reportedly told a friend who visited him that authorities had shown him screenshots of the messages and used them as evidence.
He said officials had not forced him to give his Facebook password nor seized his cell phone.
Mr Narit warned it was no longer safe to send private messages to the inbox.
"Officers showed me the screenshots and asked me whom I was referring to," Fahroong Srikhao quoted Mr Harit as saying on Facebook on Monday.
"It doesn't matter what the message is - even an invitation for a drink - they can access it. I'd like someone to ask Facebook Thailand about this and I repeat again inbox chat is no longer private," Mr Harit said.
Ms Natthika claimed she did not know Mr Harit well enough to chat with him, suggesting the evidence might have been fabricated.
Another explanation on how authorities got hold of the message screenshots is their Facebook accounts might have been hacked.
While there has been no evidence of hacking, it is no secret the Royal Thai Army bought products from Hacking Team Co, an Italian spyware vendor, in 2014.
The last theory is Facebook agreed to hand over to authorities such information, an unlikely scenario given Facebook's privacy policy.
Since the May 22, 2014 coup, Facebook has resisted requests by authorities to block some pages they found offensive.
Six days after the putsch, Facebook was inaccessible for 30-60 minutes, causing an uproar among netizens who had already anticipated some form of restriction on the popular social network.
The junta claimed a technical glitch was to blame but a telecom executive later admitted his company was instructed to block access by the junta.
Since then, Facebook has been working normally. Even today some of the pages of suspects wanted for lese majeste or political charges are still accessible in Thailand.
Section 112 of the Criminal Code, or the lese majeste law, does not limit the crime only to public sphere, so personal correspondence can be used as evidence as well.
