BANGKOK (Reuters) - A British rights activist filed lawsuits on Wednesday against Thai authorities and a major Thai fruit producer, accusing them of unlawful prosecution over a 2014 criminal defamation case against him which had been thrown out of court.

Rights activist Andy Hall has been involved in high-profile legal battles since the publication in 2013 of a report he researched for Finnish group Finnwatch on the treatment of migrant workers by Natural Fruit Company, Thailand’s biggest producer of tinned pineapples.

Last year, he was found guilty of criminal defamation over the report and given a suspended three-year jail term in a case that alarmed rights groups who feared that it could set a precedent for the use of similar charges against others.

Hall’s lawsuits relate to a separate criminal defamation case over comments he gave to Al-Jazeera television. That case was thrown out by the supreme court last year on the grounds that he was in Myanmar when he gave the interview.

In Hall’s lawsuits, he accuses Natural Fruit, nine state prosecutors, and a senior police officer of wrongful and malicious exercise of their duty. He also accuses Natural Fruit of giving false information to authorities.

“I must defend myself against an unlawful prosecution and judicial harassment,” Hall said in a statement from Brussels. He left Thailand last year.

Natural Fruit’s lawyer, Somsak Torugsa, who was also accused along with the firm, told Reuters he was not worried.

“We’re all innocent. I’ll fight it and I’ll file a counter suit,” Somsak said, without giving more details.

Somnuek Siangkong, a spokesman for the Office of the Attorney General, told Reuters he could not comment as he has not seen a copy of the lawsuit.

The senior police officer said he had no comment.

Hall also faced civil defamation cases over both the report and the television interview.

Thailand, one of the world’s key food exporters, employs an estimated 3 million migrant workers, mostly from neighboring Myanmar.