Kaczyński told supporters at a weekend meeting that, in his view, Lepper was killed by people within his own political circle because he intended to reveal sensitive information.
His remarks contradicted the official findings of a 2011 investigation, which concluded that Lepper died by suicide during a period of political decline and severe financial pressure.
Żurek said on Polsat News that anyone making such far-reaching allegations must either provide evidence or notify law-enforcement authorities.
The interview continued with a remark that prosecutors would examine whether Kaczyński holds information previously unknown to investigators.
The minister stressed that public figures cannot “throw out claims” about the killing of a former deputy prime minister without substantiation.
The politician suggested that if Kaczyński knows more, he should have informed prosecutors years ago.
Prosecutors will now assess the legal basis and procedure for a possible formal questioning of the PiS leader.
(mp)
Source: PAP/Polsat News