Pope John Paul II himself may have denied it publicly, but it's the allegation that just will not go away: Bulgaria's communist-era secret services were involved in the May 1981 attempt to shoot dead the Pontiff. This time, it is the turn of a US author and two Polish journalists to revive the claim.

To coincide with the launch in Poland of a book by US author John Koehler entitled It's About the Pope: Spies in the Vatican, Warsaw journalists Rafal Paztelanski and Grzegorz Sadowski authored an article in popular Polish weekly Wprost. The article, published on April 28, repeats the book's statement that in November 1979, nine leading Soviet Communist Party members signed a document instructing the KGB to "if necessary, reach to means beyond disinformation and discreditation" to stop the new political trend "initiated by the Polish pope". Among the signatories of the 1979 document, was then senior Soviet communist party official and later head of the USSR, Mikhail Gorbachev, the book alleges.

According to the article, Koehler found in the archives of the Stasi, the secret service of the communist East Germany, KGB documents instructing that the involvement of the Bulgarian secret services in the plot to kill Pope John Paul II be suppressed.

This document, which according to the book was forwarded by the Bulgarian secret service's active operations department to Stasi spymaster Markus Wolf in September 1982, was "later lost".

The allegation of Bulgarian involvement has been around for years. In 1983, US writer Claire Sterling released Time of the Assassins, alleging that the KGB had assigned the assassination of John Paul II to the Bulgarian secret service, who had come up with a plot involving a Turkish extremist group that worked with Bulgaria in smuggling drugs to Western Europe.

While Ali Agca went to jail for shooting John Paul II, an attempted prosecution of former Balkan Airlines representative in Rome, Sergei Antonov, came to nothing.

In March 2006, an Italian parliamentary commission found that the USSR had been behind the attempt, in retaliation for John Paul II's support for Solidarity, the trade union federation that opposed the communist regime in Poland. The commission alleged that Bulgarian secret services had worked to prevent the involvement of the USSR being exposed.

Visiting Bulgaria in May 2002, John Paul II said that he had never believed that Bulgaria had been involved in the attempt to kill him. However, a book published after his death by his secretary claimed that the Pope had believed that the KGB was behind the assassination attempt, and that privately, John Paul II had not ruled out Bulgarian complicity.

In April 2006, Wolf, by then in retirement, denied that Bulgaria had been involved in the assassination attempt.