The deputy chief investigator at Thanyaburi police station in Pathum Thani province and 12 other police officers have been accused of torturing four members of a family for information in a drug case which dates back almost 15 years.
The husband served 14 years in prison, but always insisted he was innocent.
The accusation was made in a complaint filed on Monday with the Central Investigation Bureau (CIB) complaints centre by Mon Panthasaen, 48, her 53-year-old husband, identified by police only as "Kluay", and their two daughters, aged 24 and 26.
Named in the complaint was Pol Lt Col Boonying Bandhitthai, currently deputy chief investigator at Thanyaburi police station, and 12 other officers. They are accused of attempted murder, attempted robbery and depriving minors of their freedom.
The complainants were accompanied by activist lawyer Atchariya Rangrattanapong, chairman of the Crime Victims Assistance Club.
Mr Atchariya said that in July 2007, Mrs Mon and her husband, who was a pork vendor, and their two daughters were in their house at the Ratanakosin 200 Years Housing Estate in tambon Prachathipat, Thanyaburi district.
Pol Lt Col Boonying and the other officers, who were then members of a drug suppression team in Pathum Thani, forced their way into the house and detained them. The police said there were drugs in the house.
The police searched the house, but did not find any drugs. All four of them were then taken to a petrol station in the province for interrogation, before Mrs Mon and her husband were moved to a police safe house.
At the safe house, the woman and her husband were tortured by police using electric shocks and plastic bags over their heads, demanding to know where the drugs were hidden. They could not tell them because they knew nothing about the drugs, Mr Atchariya said.
Later, another team of police investigators called, saying that nearly 4,000 methemphetamine pills had been found near the fence of the house. They were taken back to the house. There, they were forced to sign papers acknowledging the drug charges and were detained for legal action.
Mr Atchariya said he had found many questionable points in the case. One of them was the fact that police searched the house without a warrant. Moreover, another suspect, a Lao man, first told police that the pork vendor had drugs in his possession, but later confessed the drugs belonged to him.
The lawyer said he also found out that the same police team had done similar things to suspects in many other cases, but had never been subject to criminal or disciplinary action.
The pork vendor, Mrs Mon's husband, said he did not confess to the drug charges and fought the case in three courts, but was found guilty and served 14 years in jail. After being released by a royal pardon he filed for justice with the Justice Ministry and Office of the Ombudsmen, but had not received any response.
He said in filing the complaint with the CIB, he wanted legal action to be taken against the police team led by Pol Lt Col Bandhitthai for torturing his wife and mistreatment of their two children.
CIB investigators accepted the complaint and would take statements from the complainants for use with other evidence before forwarding a report to their superiors for further consideration.
Pol Lt Col Bandhitthai, when asked for comment, denied the accusation. He said he had acted within the law and would fight the case if indicted.