Sergei Antonov, the Bulgarian who was unfairly accused of involvement in the 1981 attempted murder of Pope John Paul II, has died, leaving mysteries as his legacy.

Antonov was found dead in his home on August 1 2007. He had been dead for several days before he was found, Agence France-Presse said.

Antonov was arrested in 1982 after Ali Agca, the man recorded on footage aiming a handgun at the Pope, said that Antonov had sent him a letter and a pistol with instructions to murder the Pope. At the time, Antonov was an employee of Bulgaria's Balkan Airlines office in Rome.

The trial of Antonov came to an end in 1986 because of lack of evidence against him. Antonov was released, but in bad health.

After returning to Bulgaria, Antonov was in effect a recluse, Italian news agency ANSA said, as quoted by netinfo.bg.

Antonov's name would remain forever linked to the so-called "Bulgarian trace" in the attempt to kill the Pope, ANSA said. Authorities in Italy at that time believed that the communist-era Kremlin had ordered the murder of the Pope by a Bulgarian-led team. A book by a journalist, purporting that her information was based on access to intelligence sources, aggravated this perception. Critics of the theory said that the allegations were unsubstantiated, based on nothing more than circumstantial evidence, and based on pandering to right-wing political agendas in the Western world of the time.

Agence France-Presse (AFP) said that for Bulgarians, Antonov was a symbol of the Cold War. It is not known which, or how many, Bulgarians were canvassed to support this assertion.