National police chief Chakthip Chaijinda threatened Wednesdayto sue former Democrat MP Witthaya Kaewparadai for defamation over his allegations about position buying within the police force.
Pol Gen Chakthip said he considered Mr Witthaya's claims highly defamatory, especially the one targeting the Metropolitan Police Bureau.
Mr Witthaya dropped the bombshell when he alleged position buying was rampant in police transfers and promotions involving Provincial Police Region 8, which covers the South, last year. The politician also claimed that position buying was twice as high among city police as in Provincial Police Region 8.
Following the accusations, Pol Lt Gen Thesa Siriwatho, the Provincial Police Region 8 commander, was transferred to an inactive post on Monday and an investigation was ordered into Mr Witthaya's allegations within 15 days.
Pol Gen Chakthip also dismissed as untrue speculation Pol Lt Gen Thesa's transfer was revenge against former protest leader Suthep Thaugsuban who is believed to have close links with the officer.
He insisted the transfer was to facilitate the investigation into the allegation and it did not mean the officer had anything to do with any position buying. According to the police chief, if he did nothing, he would be accused of inaction.
However, he admitted Provincial Police Region 8 had faced similar complaints over the years.
The national police chief said a fact-finding committee led by a police inspector-general is likely to interview Mr Witthaya for more information and urged the politician to hand over all evidence he had to the committee.
He also rejected an observation that Patrol and Special Operation Division chief Pol Maj Gen Surachet Hakpal might have influenced police transfers, saying he was not involved.
Pol Gen Chakthip said Pol Maj Gen Surachet was instructed to verify certain information or scrutinise the backgrounds of some figures, including police officers, so some people might misunderstand.
In fact, he had nothing to do with decision making, said the police chief.
"I was solely responsible for police transfers which were carried out in line with the law and the NCPO's order. The claim that someone bigger than me was involved isn't true. I am the highest in the chain of command in the force," he said.
Pol Maj Gen Surachet has close ties with Deputy Prime Minister Prawit Wongsuwon, who oversees police affairs, so he could be seen to have influence over reshuffles, said police sources.
Pol Lt Gen Thesa, who returned from an overseas trip Wednesday, denied there had been position buying under his watch.
In a brief news conference in which he refused to answer reporters' questions, he said he welcomed the fact-finding probe.
Deputy chairman of the National Reform Steering Assembly Alongkorn Ponlaboot called for an investigation into the matter.