Activist Andy Hall has filed a complaint with the Royal Thai Police office, accusing Bang Na police of malfeasance in pressuring him to sign a confession in a defamation case filed against him by a local cannery company.
The British activist also informed the National Human Rights Commission and the British embassy about the two suits filed against him by Natural Fruits Co.
Mr Hall said his lawyer was preparing a counter-complaint against Bang Na police for failing to properly investigate the allegations lodged against him by Natural Fruits.
He said the case was based on an interview he gave to Al Jazeera in Myanmar and should not be within Thai legal jurisdiction.
The Prachuap Khiri Khan-based firm filed a lawsuit against Mr Hall in February, accusing him of violating the Computer Crime Act by disseminating his research, commissioned by Finnwatch, which alleged migrant labour abuses at its factory.
Mr Hall could be ordered to pay the company 300 million baht in compensation if found guilty.
The company then filed a defamation complaint against Mr Hall on Sept 28, accusing him of broadcasting false information about Natural Fruits.
A video posted on YouTube, entitled "Migrants work in poor conditions in Thailand", featured Mr Hall's research into alleged labour rights violations committed against migrant Myanmar workers at the Natural Fruits factory.
"The claims in question relate to an interview I gave to Al Jazeera in Myanmar," Mr Hall said. "This case should not be within the jurisdiction of Thai police, so they had no right to investigate and call me for questioning."
Mr Hall said Bang Na police had tried to get him to sign a confession without a proper English translation, which was an abuse of the justice process.
"The Thai ministries of Foreign Affairs and Justice, as well as the British ambassador and the NHRC, are now aware of my case," said Mr Hall, who has been discharged from a short-term consultancy contract in Myanmar for unknown reasons.
The British embassy said its officials in Bangkok are aware of the case and have been in regular contact with Mr Hall and provided him with appropriate consular advice.
The European Union (EU) sent a delegation to the first hearing on the case against Mr Hall in April 2013 and continues to follow the proceedings.
The EU is negotiating a free trade agreement with Thailand, with the issue of workers' rights a continuing concern across Thailand's fishing industry and in all factories exporting goods to Europe.
"The case is between two private parties and is now before a Thai court," the EU said.
"The EU will continue to follow the trial with full respect for the independence of the Thai judicial system."