Deputy Prime Minister Prawit Wongsuwon has brushed off scepticism the regime is now aiming to purge all local Chiang Mai politicians with Pheu Thai links following recent arrests.
Eleven people, including Chiang Mai politicians, are facing charges in relation to letters containing allegedly distorted information on the draft charter discovered in the province during raids on Saturday.
Gen Prawit said they were charged with inciting public unrest under Section 116 of the Criminal Code. They will be kept in custody for seven days in line with the National Council for Peace and Order's (NCPO) procedures before being arraigned at a military court, he said.
"The move was not intended to wipe out the politicians in Chiang Mai," Gen Prawit said, adding authorities were not aware the offence related to the referendum would happen in Chiang Mai. Arrests were made based on evidence, he said.
Officials found the letters during raids on six locations linked to Boonlert Buranupakorn, president of Chiang Mai Provincial Administrative Organisation (PAO). Mr Boonlert, whose family is known to have close Pheu Thai links, is said to be travelling abroad.
On Wednesday, army officers arrested Mr Boonlert's niece, Tasanee Buranupakorn, who is also the vice-president of the Chiang Mai PAO, who turned up at the Royal Thai Police headquarters in Bangkok to seek justice for her younger sister, Thanthip, who was apprehended at her home in Chiang Mai on Tuesday night.
Khachen Jiakkhajorn, mayor of tambon Chang Phueak in Chiang Mai's Muang district, was also charged in connection with the offending letters.
The alleged offenders are in custody at the 11th Military Circle in the Dusit area.
Key Pheu Thai figure Chaturon Chaisang said the suspects should not have been charged under Section 116 nor be prosecuted at the military court. They should have been charged under the referendum law, he said.
The move deprives people of their freedom of expression as the NCPO fears the draft charter will fail, he added.
Mr Chaturon was speaking as Pheu Thai members and red-shirt leaders arrived at the 11th Military Circle to visit Ms Tasanee yesterday.
The politicians and Ms Tasanee's lawyer, Jamnong Chaimongkol, were denied access to Ms Tasanee.
Mr Jamnong said he would seek bail for Ms Tasanee and Ms Thanthip today, adding Ms Tasanee is suffering from several health ailments.