Police take former Nakhon Sawan MP Banyin Tangpakorn to the Crime Suppression Division for interrogation on Sunday. (Photo by Nutthawat Wicheanbut)

Banyin Tangpakorn has denied two new charges pressed against him by police after the former MP for Nakhon Sawan was arrested at his house on Sunday morning.

"I still do not know what this is all about," the former deputy commerce minister told reporters as he walked into the Crime Suppression Division (CSD) in the afternoon with police escorting him.

Central Investigation Bureau (CIB) chief Pol Lt Gen Suthin Sapphuang said later the former politician has been charged with colluding with others on murder and ransom in relation to the disappearance of Veerachai Sakunprasert. The body of the missing person has not been found.

The CSD is a unit under the CIB.

Mr Veerachai is the elder brother of judge Panida Sakunprasert, who is in charge of the case in which Pol Lt Col Banyin has been indicted for falsifying a share-transfer document.

Pol Lt Col Banyin, 56, was arrested by the CSD special force Hanuman at his house in Muang district of Nakhon Sawan on Sunday morning. Police then took him to the CSD for interrogation and charges. Police also arrested two other suspects identified only as Manas Thapnil, 67, and Narongsak Pomchan, 49. All were wanted under arrest warrants issued by the Criminal Court on Feb 19.

Judge Panida is due to deliver the ruling on the case at the South Criminal Court on March 20. The case involves fake documents used to transfer about 300 million baht in shares to the former deputy commerce minister from late construction Chuwong sae Tang in 2015.

Police believed the abduction of the judge's brother is directly connected with the case.

Chuwong was killed in a road accident in a car driven by Pol Lt Col Banyin. The murder case was investigated, but the court withheld the ruling pending the decision on the share transfer case.

Plot and threats

Court of Justice secretary-general Sarawut Benjakul spoke out on Sunday about the case, saying CCTV cameras had captured the suspects waiting for one hour before they abducted Mr Veerachai at the South Criminal Court on Feb 4. He said at least three people were seen, but refused to say whether one of them was Pol Lt Col Banyin.

The abductors took Mr Veerachai to a waiting vehicle at 5.30pm on Feb 4.

CSD police said one of the suspects called judge Panida by phone, pressing her to dismiss the defendant's case when the ruling is delivered in exchange for the release of her brother. If she failed to heed the threat, his brother would "go missing", the police said.

The judge later filed a complaint over the threat to her life with police, including the recorded conversation between her and the caller.

"The abduction of a hostage to affect the court ruling is serious and is unprecedented in the Court of Justice," Mr Sarawut said. Judge Panida is under the protection of the police and court marshals, he added.

It remains unclear why Mr Veerachai was at the court that day.

Police believe he was murdered after the judge refused to comply.

Killing spots

Police tracked the abductors after the judge sought help from them before requesting the court approve the arrest warrants for the three.

The body of Mr Veerachai was believed to have been burnt and dismembered in Takhli district of Nakhon Sawan, before the body parts were put in bags and dropped into the Chao Phraya River in Muang district, according to the CSD.

National police chief Chakthip Chaijinda flew to the province on Sunday to examine the evidence. He went to Ban Kradee in Takhi district -- where the brother of the judge was believed to have been slain -- and then to Ban Klang Daed in Muang district where the bags were dumped.

Pol Gen Chakthip ordered divers to quickly search for the bags in order to use them to substantiate the allegations involving at least three other suspects besides Pol Lt Col Banyin.

Police also searched 19 locations in Nakhon Sawan and two in Bangkok on Sunday as part of the investigation.

Daughter's reaction

Bussaya, a daughter of the former politician, followed her father to the CSD and called for justice for her family.

She said she was confident in her father's innocence and said he could have been framed by his enemies.