Frances Kennedy Rome

In recent weeks, Italian courts have put under house arrest three separate Mafia killers who have been collaborating with the police.

The magistrates' rulings have provoked consternation in the public and fuelled a debate about the law governing the "pentiti", the Mafia members who provide inside information to the police in return for protection and reduced prison terms.

The three men involved were all leading figures in the Sicilian Mafia, with chilling criminal records.

Judge Falcone: Murdered by the Mafia

Enzo Brusca dissolved the body of an 11-year-old boy in a vat of acid, Giovanni Drago is accused of killing 40 people and Salvatore Cancemi was among those responsible for the car bomb murder of Judge Giovanni Falcone.

As well as confessing to their own crimes, all three Mafiosi have provided vital inside information to investigators.

As collaborators of justice they're entitled to police protection, a living allowance and a reduction in their prison terms and conditions.

The decisions to grant them house arrest are technically legitimate but ethically hard to swallow and have prompted a heated debate in Italy.

There have been calls for an overhaul of the law governing Mafia informers, a recurrent theme of the centre-right governing coalition which is keen to limit the power of the judiciary.

The justice minister has ordered an inquiry and suggested that magistrates should interpret the law according to public opinion.

Anti-Mafia magistrates argue that the pact between the authorities and the former Mafia members is in the state's interest.

Only through the contribution of informers have countless crimes been solved and other Mafia members arrested.

Maria Falcone, the sister of the murdered judge, said the informers were important but there must be a balance.