The autobiography of a jailed Mafia killer has been selected as finalist for a Sicilian literary award, prompting the resignation of a juror who claimed the choice offended the memory of the author's victims.

Literary critic Gaspare Agnello said that the decision to admit a book by cosa nostra affiliate Giuseppe Grassonelli to the final has soiled the name of the prize dedicated to Leonardo Sciascia, a late Sicilian writer who helped raise awareness on Mafia issues through his work.

Noting that the mobster never repented of his crimes, Agnello said that awarding him "would be an offence to his many victims, whose blood is still fresh".

To add to the controversy, one of the other selected finalists, Caterina Chinnici, is the daughter of a prosecutor killed by the Mafia in a 1983 bomb attack in Palermo.

Grassonelli, from the southern port town of Porto Empedocle, was arrested in the early 1990s over a series of murders he allegedly committed in revenge for the killing of members of his family during a turf war.

The 49-year-old Mafioso was sentenced to life without parole, as he refused to cooperate with Italian authorities as a pentito (informer).

His book, Malerba - Italian for "bad grass", the nickname Grassonelli was given in his youth - tells of his vengeance and criminal life.

Almost illiterate when he entered jail, the mobster has dedicated time behind bars to study and recently graduated in literature and philosophy, the book publisher said.

According to critic Agnello, the killer's new life however did not cleanse his past atrocities.

"How is it possible that a life convict who committed brutal crimes ... takes part in a literary award that had in Sciascia one of its leading figures?" Agnello wrote in a letter announcing his resignation to newspaper La Sicilia.

Malerba's co-author, journalist Carmelo Sardo, dismissed the criticism as fuelled by "unexplainable envy" and accused the literary critic of failing to understand the book's value and message.

The president of the jury, Gaetano Savatteri, said that the names of the three finalists were agreed by all board members, including Agnello.

The winner is to be announced at the weekend in the picturesque Sicilian town of Racalmuto, near Agrigento.