One of Spanovic's lawyers, Silvije Degen, told Hina on Tuesday that the Supreme Court had turned down the guilty verdict against his client due to breaches of the criminal procedure by the Sisak court.
The lawyer said that he had not yet received the Supreme Court's ruling in writing, which he added was why he could not give other information about the latest decision.
Degen said that his client, who now lives in London, would be willing to come back to Croatia for a retrial.
Spanovic, who insists on his innocence, thus faces a third trial for this case.
In 1994, the Sisak County Court tried him in absentia and sentenced him to 20 years in prison. An international warrant for his arrest was issued afterwards, and he was arrested in Britain in 2006 and extradited to Croatia in August 2009.
After his transfer to Croatia, the Supreme Court had approved the first retrial, at which Spanovic was found guilty and was given a 42-month jail sentence.
The Sisak court's trial chamber said then that it reduced the length of Spanovic's prison term because the ruling was based on witnesses' statements and not on material evidence. He was released from custody, because he had spent three and a half years in pre-trial detention in Britain and in Sisak.