Pope's attacker says: I want Dan Brown to tell my story

The man who came within a whisker of murdering Pope John Paul II and later claimed to be Jesus Christ was released from jail in Turkey yesterday and promised to tell all – for a price.

Mehmet Ali Agca has been in jail for nearly 30 years and during that time, the theories about why he attempted a papal assassination have multiplied. Now he is out, the curiosity about the man and his motives will be vast. And Mr Agca, despite having what the Turkish authorities called "a severe personality disorder", seems well aware of it.

Interest in film and documentary projects stretches "from Japan to Canada", he claimed in a letter to a British newspaper. He is reported to be asking $2m (£1.2m) for a television interview, and $5m for two books, one of which would be his autobiography. He has also apparently written to the best-selling American author Dan Brown proposing a book to be entitled The Vatican Code, and a film of the same name.

Hurriyet Daily News, a Turkish daily paper, reported that his family hopes "to earn at least $50m in copyrights from TV series, interviews, documentaries and books".

But asked for details of the deals, Agca's lawyer, Yilmaz Abosoglu, was a little evasive. "We have yet to agree with any television or publishing company," he told reporters. "We'll wait and see what happens."

Tall, erect and dressed in a royal blue suit and tie, Agca, now 52, emerged from Sincan Prison in Ankara yesterday and did not disappoint the host of reporters waiting for him. "I proclaim the end of the world," he told them. "All the world will be destroyed this century. Every human being will die in this century ... I am the Christ eternal."

In a handwritten letter given to reporters outside the jail by his brother, he announced that he was "the divine messenger of God" and promised to write "the perfect Gospel".

The biggest question dogging Agca all these years has been why he wanted to kill the pope. John Paul II, dynamic, fiercely anti-communist and Polish, was greeting pilgrims in St Peter's Square on 13 May 1981 when the young Turk took aim from a few yards away and shot him twice in the stomach. Cries went up from the crowd – "Hanno sparato il papa!" (They've shot the Pope!) – as the pontiff slumped to his seat and bloodstains spread across his cream-coloured cassock.

Agca was caught as he tried to escape. But while there was no doubt about his guilt, his motive remains deeply obscure.

Under interrogation he claimed that he had carried out the shooting according to orders from Bulgarian secret intelligence. But later he abruptly changed his story and began issuing apparently crazed declarations, claiming to be Jesus Christ and announcing the end of the world.

Other theories about the attack abound. In 1984 a Mafia supergrass claimed that Toto Riina, Cosa Nostra's then capo di capi, was behind it. One Italian magistrate argued that Carlos the Jackal was involved.

Agca himself claimed to be the fulfilment of the "Third Secret of Fatima", a testament supposedly revealed by the Madonna to Portuguese shepherds in 1917, which predicted the assassination of a pope.

Whether he will now enlighten us, or merely confound the confusion further, remains to be seen. As does any book or film deal.