Officials in Italy are expressing outrage over Brazil's decision to free an Italian fugitive wanted for murder.

Victims and officials described as a slap in the face the ruling Wednesday by Brazil's Supreme Court to release former left-wing militant Cesare Battisti.

Italian Foreign Minister Franco Frattini promised to pursue his country's claims with the International Court of Justice in The Hague.

Battisti left the Brazilian prison Thursday, where he had been held. The 56-year-old has long said he is innocent of any crime.

Italian prosecutors blame Battisti for four murders dating from the 1970s when he was a member of an armed communist movement.

He had been on the run since the 1980s, when he escaped from an Italian prison while awaiting trial. He was convicted in absentia of two of the murders, and was re-arrested in 2007 in Brazil.

Battisti faces possible life in prison if he returns to Italy.

In 2009, Brazilian authorities angered Italy when they granted Battisti political asylum, saying he risked persecution if extradited. Former Brazilian President Luiz Inacio Lula da Silva also decided last year to deny Italy's request for extradition.