According to state body the Institute for National Remembrance (IPN), which has the power to prosecute, Kisczczak's widow had proposed to sell security services documents from the 1970s to the institute regarding the so-called agent 'Bolek', who some historians claim was Wałęsa.
Wałęsa, who led the pro-democracy Solidarity trade union in the 1980s and later became president of Poland after the end of the communism regime, has long wrestled with acccusations that he was an informant during the 1970s.
Kiszczak, who was a key figure in the imposition of martial law in 1981, died aged 90 in November 2015.
According to a statement released by IPN, Tuesday's action at the house of Kiszczak's widow “was aimed at securing documents” which the institute insists must be released by law to IPN.
Wałęsa himself, who had proposed a debate about the spy allegations with IPN earlier this year but later backed out, slammed yesterday's action on his blog.
“They even fight over the dead body of Kiszczak,” he wrote.
“You are not able to change the true facts through lies, slander and forgeries,” he continued, adding that “it was I who in stages safely led [the country] to a complete victory [over the communist regime].”
Claims and counterclaims
Wałęsa's alleged cooperation with the communist security services (SB) followed the repression of strikes in Gdańsk and its environs in 1970. Wałęsa had taken part in the protests.
He supposedly broke off ties with the SB several years before the landmark 1980 strike at the Gdańsk Shipyard, a protest that led to the birth of the Solidarity trade union and his meteoric rise to international fame.
Although he has strenuously denied the accusations in Poland, in 2011 he told the UK's Guardian newspaper that he had played “a game” with the secret services.
“It was all a clever game,” he told the daily.
“It was important to play it to give the impression I was weak, so as not to be eliminated.
“Not for a moment was I on the other side,” he insisted. (nh/pk)