Former Polish president Lech Walesa Friday denied fresh claims that he was a communist-era informant, but admitted making a mistake.
"I did not collaborate with secret police, I never took money, but I did make one mistake," Walesa wrote on his social media profile, adding that he vowed not to reveal what mistake this was.
"There is a man, a perpetrator, who is still alive and can reveal the truth, I'm counting on that," Walesa said Friday from Venezuela.
Personnel records for Walesa and a letter of formal obligation to cooperate with intelligence services were found in the house of former Polish general Czeslaw Jan Kiszczak, who died in November, institute director Lukasz Kaminski told the Polish Press Agency on Thursday.
Kaminski confirmed that Walesa's signature was authentic.
He later told the news station TVN24 it could not be assumed that the contents of a genuine secret police document reflected the truth.
Walesa has for years denied speculation that he was an agent for the security establishment under the code name Bolek.
Walesa was previously the leader of the Soviet bloc's first independent trade union known as Solidarity, and was the first democratically elected president of Poland, from 1990 to 1995.