The abuse was uncovered when a former police informant found out late last year that her daughter was among a group of underage prostitutes. She has since fought to expose the scandal and bring the culprits to justice.

Now, the spotlight is on the sex trade in Mae Hong Son province, where at least three girls were allegedly forced into prostitution.

Pol Senior Sgt-Major Yutthachai Thongchat, who worked at the Nam Piang Din Police Station in Mae Hong Son province until the scandal broke out, has been charged with human trafficking for procuring minors for sex along with two women, Piyawan Sukma and Piyathas Parpthiensuwan.

“These two women threatened to post a video clip on Facebook showing me taking drugs, which they encouraged me to try, if I refused to join the flesh trade,” the daughter of the complainant said on condition of anonymity. “The first time took place in November 2013.”

The girl, now 19, said she was given Bt1,000 for the sex each time, while her procurer took another Bt1,000 from her customer.

In the following years, she had have sex for money about 10 times a month and she found out that other girls were also trapped in the same fate.

Another girl said she was a student in junior secondary school when a friend introduced her to Piyawan and Piyathas in February 2014. “About one week after the introduction, Piyawan brought me to a hotel and told me to do what the customer wanted for money. If I didn’t obey, I would be hit,” the girl said. “That day, I was paid Bt1,000.”

She said she had since tried to avoid Piyawan, who kept calling her to ask her to get involved in prostitution.

“But one day, I ran out of money and decided to return to her,” the girl said. She ended up being sold for sex almost every day for more than two years. On some days, she had to serve up to four customers. Finally, she fled to another province.

Another alleged victim said Yutthachai once threatened to run her and other young prostitutes out of Mae Hong Son if they refused to serve his customers.

“This is a very detailed matter. The Navy needs time to proceed with the information so as to provide a holistic explanation,” Supreme Commander General Surapong Suwana-adth said.

“This kind of information isn’t usually made public. If we reveal what kind of instruments we’re going to equip it with, other [countries] might use more advanced technology against us,” he said. “But I insist that they are essential to create a military balance [in the region].”

Little is known about the Navy’s procurement of the three S26T Yuan-class submarines from China, worth a total of Bt36 billion. Authorities have offered some explanations about their security and economic reasoning as well as broad procurement timelines, but have yet to provide documented details to the public.

Recent speculation was that the hardware would be brought to the Cabinet after the official launch of a submarine port in Chon Buri last month. The junta-backed government, however, said nothing until a week after they had already approved the multi-billion deal in secret. Meanwhile, activist Srisuwan Janya plans to file a petition with the Office of the Auditor-General today to investigate whether the submarine purchase violated the Constitution and relevant laws.

Srisuwan said the procurement could violate the 2017 Constitution, which requires the government to strictly maintain financial and fiscal discipline for public benefit.

He expressed doubts as to whether it was necessary to buy a submarine – not only because of the amount of money it entailed amid the country’s economic downturn, but also its practicality.

“The Gulf of Thailand has an average depth of 25 to 60 metres,” he said. “We’re also not in conflict with any neighbouring countries. There is no reason to accumulate such hardware.”

The procurement process was also far from transparent, Srisuwan said, adding the government had not revealed additional costs such as dock construction, hiring of personnel, supplementary hardware and annual maintenance.

In a related development, most respondents to a Twitter poll conducted by the Nation News Agency (NNA) disagreed with the government’s approval of the submarine procurement. Of the 1,705 respondents, 81 per cent said they disagreed, compared to 9 per cent who backed the green light for the submarine purchase.

Opponents of the plan pointed to the country’s still-weak economy while supporters said the country needed submarines for security reasons.

Sa Kaew police chief Pol MajGeneral Yingyot Thepchamnong said 200 Cambodians were found hidden in a house and the longan orchard belonging to a couple, Panas and Noi Plathong, in the district.

The raid was conducted after police received a tip-off about their presence in the district.

A Cambodian who identified himself only as Wue, 25, of Battambang province in Cambodia, said that he had previously worked as a construction worker in Chacheongsao province for about Bt300 per day.

However, he returned home during the Songkran festival earlier this month and to come back to Thailand he had to pay a middle man Bt2,500 to take him to his destination.

He and 200 others Cambodians sneaked on foot from Cambodia to the border province of Sa Kaew on Tuesday and arrived in Thailand at about 9pm. They then gathered at the field before being arrested.

Yingyot said that the arrests were the work of combined forces.

He said some of the Cambodians had walked for three days before arriving in Sa Kaew and hid in the orchard waiting for transportation to their destinations.

Officials will provide them with food and shelter on a humanitarian basis before deporting them. Police will extend the investigation into the smuggling ring that brought them into the country, he said.

A lower rent would allow the department to transfer the tourist attraction to Tambon Krasom Municipality.

Department of Tourism deputy chief Santi Pawai along with Takua Thung district chief Sarawuth Thanacharoensakul and Tambon Krasom mayor Anurak Antimanon inspected the attraction on Wednesday.

Santi said Phang Nga Treasury Office would co-ordinate with their head office to find an appropriate rent rate so the municipality could afford to rent and operate the facility for tourists.

“Since this building is constructed by taxpayers’ money, we should find a way to make use of it. I’m confident this would be an impressive tourist attractions for both Thai and foreign visitors,” he said.

The attraction located at the Surakun port, which reportedly cost Bt40 million to build, was designed to showcase the 1974 movie, The Man with the Golden Gun, which was filmed in Thailand.

The facility – fully equipped with film props, a theatre for sound and light shows and a gift shop – was officially launched in 2014 but it has been closed to tourists and left to ruin due to contractual problems.

The Department of Tourism was required by law to transfer the facility to the Treasury Department. The initial intention of handing it to the Tambon Krasom Municipality was shifted to having the municipality run it on a rental basis. The Treasury Department initially quoted the rent rate of nearly Bt200,000 a year.

Srisuwan said the procurement, proposed by the Royal Thai Navy and approved by the Cabinet last week could violate the 2017 Constitution, which requires the government to strictly maintain financial and fiscal discipline for the public benefit.

He expressed doubts as to whether it was necessary to buy a submarine – judging from not only the sum of money to be spent amid the country’s economic downturn, but also its practicality.

“The Gulf of Thailand has average depths of 25 to 60 metres,” he said. “We’re also not in conflict with any neighbouring countries. There is no reason to accumulate such hardware.”

The procurement process was also insufficiently transparent, Srisuwan said, adding that the government had yet to mention additional costs as dock construction, personnel hiring, supplementary hardware and annual maintenance.

Meanwhile, most respondents to a Twitter poll conducted by the Nation News Agency (NNA) disagreed with the government’s approval of the submarine procurement. Of the 1,705 respondents, 81 per cent said they disagreed, compared to 9 per cent who agreed to the green light for the submarine purchase.

Opponents of the plan pointed to the country’s still weakening economy while supporters said the country needed submarines for security reasons.

“I don’t think the submarine should be bought while the country suffers from an economic downturn. This same amount of money should have been spent on something else more beneficial,” said Lawan Krongboon, a respondent to the NNA poll.

Another respondent, Santisak Fuengvanich, said: “I agree with this [submarine purchase]. Although people’s wellbeing is not in good shape, Thailand needs the submarines for security reasons. People need to be reasonable and take a holistic look at our country.”

Siripimol Thanpatthanawit, a respondent to the online survey, said: “Whether we agree with this or not, the Cabinet has already approved it. Do they care about us? If they did, they would not go this far. As a member of the public, I’m disheartened!”

As the central venue of the historic event will be Sanam Luang ceremonial ground in Bangkok, where the royal funeral pyre is located, booths will be set up in designated areas for mourners to participate in the funeral flower-laying ritual.

Wissanu said each booth will feature the same portrait of the late King that is installed in front of the royal urn in the Grand Palace. He also said there was a possibility that more public holidays would be declared during the royal cremation ceremony, as the responsible committee was currently considering the matter.

Chonthicha Jaengrew, a member of New Democracy Movement, posted on Facebook on Tuesday that she had been contacted by a person claiming to be a police officer who told her to stop investigating or taking any other action regarding the missing plaque. She could be prosecuted on national security charges, including lese majeste, she was warned.

Prior to Chonthicha’s case, two other pro-democracy activists who have protested the disappearance of the plaque, Sirawith Serithiwat and Piyarat Chongthep, posted similar message on Facebook about being called by police and warned against activities concerning the plaque.

The plaque was reported missing two weeks, when a replacement know as the so-called “Na Sai”, or “happy face people” plaque, was discovered.

Government officials have made vague statements and avoided taking any action on the matter.