Mr Hamkin's DNA profile was kept on record by police after he was convicted of drink driving in 2001.
He added: "It was a stupid thing to do but I never thought it would land me in court accused of murder."
At Bow Street, Mr Hamkin had to find a £10,000 surety before magistrates agreed to grant him bail when he faced an extradition warrant on February 16.
Mr Hamkin, who has a twoyear-old daughter Alicia, is consulting his lawyer with a view to suing police for wrongful arrest and false imprisonment.
His solicitor, Rex Makin, said: "The police say that a 'more refined result' from a second DNA sample that shows that he is not a match for the Italian killer.
"I suspect that the original DNA sample was bungled and that has resulted in this terrible experience for Mr Hamkin.