Polish special services forced their way into the home of a former justice minister on Tuesday, a prosecution spokesperson said, as part of an investigation into alleged misuse of funds under the previous government, according to Reuters.
Poland's pro-European coalition government has said that those it accuses of breaking the law during eight years of nationalist rule until December will be held to account by prosecutors who it says are now free of political influence.
Lawmakers connected to the former Law and Justice (PiS) administration accuse the new government of carrying out a witchhunt.
Przemyslaw Nowak, a spokesperson for the state prosecutor's office, said four people had been detained as part of an investigation into alleged misuse of money from the Justice Fund, set up to help victims of crime.
Some media reports have accused former justice ministry officials of using the fund to curry favour among voters, such as by buying fire engines or equipment for village halls in conservative-minded rural constituencies.
Nowak said three of those detained were former justice ministry officials and one was a beneficiary of the fund.
He confirmed reports that the home of former Justice Minister Zbigniew Ziobro, who is being treated for cancer had been searched.
"Mr Ziobro was not at home," Nowak told reporters. "Prosecutors contacted the family asking them to open the premises, but it turned out to be ineffective... The door was broken enough to allow entry into the apartment."
Ziobro was the architect of judicial reforms that critics said undermined the independence of the courts. He has previously denied any wrongdoing.
Patryk Jaki, a member of the European Parliament from Ziobro's Sovereign Poland party, which ruled in coalition with PiS, called the search of the former justice minister's home a "gangster act."
Ziobro's lawyer, Maciej Zaborowski, told reporters that to his knowledge nobody was present at the property at the time of the search and nobody tried to contact the owners.
Nowak said the investigation was a "serious criminal matter and has no political undertones."