Polish President Andrzej Duda has pardoned a former head of the country's anti-corruption agency who was found guilty of abuse of power, a gesture slammed by the opposition as politically motivated, Reuters reported. A Polish court sentenced Mariusz Kaminski in March to three years in jail for actions he took while head of the agency in 2007 to combat corruption. He had appealed against the verdict. Kaminski is close to Jaroslaw Kaczynski, leader of the conservative, eurosceptic Law and Justice party (PiS) which has just returned to power after winning an Oct. 25 parliamentary election. Kaminski is now due to take up a post in the new administration. PiS was last in government in 2007, when Kaczynski was prime minister and Kaminski ran the anti-corruption agency. "In the president's view, this case had a political character," presidential adviser Andrzej Dera told reporters. "People who fight corruption ... deserve special protection," Dera said, adding that Kaminski was a very honest man whose integrity had never been open to question. Duda became Poland's president earlier this year after winning an election with the backing of PiS. Critics said Kaminski and his associates had pursued graft with excessive zeal when in office, using methods they said sometimes circumvented laws and also hounded innocent people. Kaminski argued that corruption was a blight on Polish democracy that had to be tackled thoroughly. Poland's new prime minister, Beata Szydlo, has named Kaminski to take responsibility for the secret services in her new administration. The main opposition Civic Platform (PO) party, which governed Poland from 2007 until last month, said the presidential pardon was aimed at freeing Kaminski up to assume his new role without fear of eventual conviction. "This (pardon) is an unprecedented attack on the rule of law," said Slawomir Neumann, head of the PO's parliamentary caucus.