Allegations that former president Lech Walesa was a communist-era secret informer have resurfaced after prosecutors seized documents illegally held by a communist-era official's family.

Nobel Peace laureate and Solidarity founder Walesa has repeatedly denied the allegations and was cleared by a special court in 2000.

A spokeswoman for the state National Remembrance Institute said Wednesday that its prosecutors seized documents from the house of the late Gen. Czeslaw Kiszczak, who was the last communist-era interior minister.

The papers came to light when Kiszczak's widow offered to sell the institute documents concerning secret informer "Bolek," a codename mentioned in the allegations over Walesa. Prosecutors seized the documents because the law required them to have been handed in.

It was not immediately known whether the documents were authentic or what they contain.