Mae Hong Son governor Suebsak Iamwicharn was involved in the sex trade scandal in his province, deputy national police chief Srivara Ransibrahmanakul insisted Thursday.
There was sufficient evidence to prove the allegation, he said, adding he was unable to provide details yet as it could affect the investigation.
Pol Gen Srivara said police have not summoned Mr Suebsak since the provincial governor has already been questioned by a disciplinary panel set up by the Interior Ministry.
The governor was previously implicated by the mother of a girl forced into prostitution, who said that Mr Suebsak was a client of the human trafficking gang.
The deputy national police chief said he already assigned Pol Lt Gen Poonsup Prasertsak, chief of Provincial Police Region 5 in charge of the North, to speed up the investigation.
As for the three policemen involved in the case, Pol Gen Srivara said there was not enough evidence to issue arrest warrants for them as a disciplinary panel found they could be only considered as clients.
The three are a deputy superintendent, a deputy inspector and a non-commissioned officer.
Besides, the probe has not found any high-ranking policemen involved in the sex trafficking yet, he said.
Pol Gen Srivara, however, vowed legal action will be brought against any officials linked to the illegal trade.
He also assured the public there were no scapegoats in the case.
The probe will also be widened to investigate the mother's claim in which she said her daughter was forced to use drugs and gang-raped during the period when she was forced to provide sex, he added.
The mother also handed over a record Thursday of a phone conversation between her and an Internal Security Operations Command officer, who mistook her for being a sex service procurer, to the Anti-Trafficking in Persons Division.
According to Keodpol Kaewkeod, the mother's lawyer, the officer said a high-ranking official would help the procurer escape arrest.
Meanwhile, Mr Suebsak was questioned for four hours Thursday by a five-member panel, led by interior deputy permanent secretary Prayoon Ratanasenee, in Mae Hong Son. Six witnesses, who are local officials, were also summoned to give statements.
After the probe, Mr Suebsak insisted on his innocence but declined to give interviews to the media, saying he was instructed not to disclose the probe details as the investigation was under way.
Mr Suebsak said he would respect the inquiry results when they come out.
Interior permanent secretary Kritsada Boonrat said the investigation has not been completed yet as the panel needs to summon other witnesses to testify.
The probe results are expected within 30 days, he added.
Meanwhile, Prime Minister Prayut Chan-o-cha insisted legal action must be brought against all state officials in connection with the alleged sex trade.
"Since the first day I heard the news, I ordered relevant authorities to strictly enforce the law against officials at all levels who are found linked to the case. No exceptions," he said.
Also Thursday, the Criminal Court approved a police request for the first period of detention for three suspects: two female sex procurers and a Mae Hong police officer who were arrested earlier.
They are being held in police custody until May 8 as investigators need to gather more evidence and run background checks on them and other people involved.