Police are keeping a close eye on former anti-Yingluck Shinawatra protest leader Suthep Thaugsuban after he urged his supporters to "blow whistles" to encourage people to vote in tomorrow's referendum on the draft charter.
The officers were alerted to the call during a live video broadcast on Mr Suthep's Facebook page on Tuesday which aimed to send a signal to supporters of the now-defunct People's Democratic Reform Committee (PDRC) to exercise their rights on polling day.
The whistles brought back images of the PDRC's months-long mass street demonstrations against the Yingluck administration in 2014, during which they blew the whistles as a symbol of their unity to expel allegedly corrupt politicians and call for national reform.
Their protests were a precursor of the coup on May 22 that year.
The police, who once struggled to contain several thousand of these protesters, are very aware of the political implications of the whistling, so this time "we'll carefully listen to the intentions" of Mr Suthep, national police chief Chakthip Chaijinda said yesterday.
In a part of the video, Mr Suthep was seen showing a whistle as he was asking his supporters who "fought side by side" to "let the whistle sounds excite people across the country, so they have the urge to carry out this important duty for the nation".
He also reiterated his own interpretation of the draft charter which matches the PDRC's calls for reforms, particularly measures against corruption.
Mr Suthep said he only said what he thought, and that no matter whether people vote for or against the constitution, he respects their decisions. "I just want you to go to the polling booths," he added.
Deputy national police chief Pol Gen Srivara Ransibramanakul is checking the video message.
If anyone is found to have violated any laws, they will certainly face legal action, vowed Pol Gen Chakthip.
Police officers across the country have been strictly ordered to look out for irregularities aimed at disrupting the referendum.
Deputy Prime Minister Wissanu Krea-ngam also asked security officers to review another video message that was posted by Mr Suthep on his Facebook page on Thursday.
The former Democrat MP allegedly said if the draft charter was shot down, former prime minister Thaksin Shinawatra and his supporters, referred to by Mr Suthep as "they", would use the result to justify a move to oust the Prayut Chan-o-cha government.
Mr Wissanu declined to comment on the content he has not yet watched, but he said he personally disagrees with anyone who talks about "issues which are not theirs".
He said they should focus on their own issues.
