Graham King's GK Films has acquired feature rights to the true-life story of former mobster John Martorano, who was released from prison in 2007 after serving 14 years for murder.

King, who recently completed shooting the thriller Edge Of Darkness starring Mel Gibson on location in Massachusetts, will produce the feature. He was introduced to Martorano by former Massachusetts police detective Thomas B Duffy, a 30-year veteran of the force who served as a technical consultant on Edge Of Darkness as well as The Departed.

'When I first met John, I was struck by his unyielding sense of loyalty to those close to him,' King said. 'It was this loyalty that drove him to commit some of his terrible crimes and in the end to also co-operate with authorities. John has had a complicated life and it will be a fascinating story to tell the world.'

Martorano murdered 20 people during his ten-year reign as chief enforcer for Boston's Winter Hill Gang, run by James 'Whitey' Bulger. After he learned that his main comrades had deceived him and were top government informants all along, he turned government's main witness to expose a web of corruption and collusion involving the mob and the Boston office of the FBI.