Italy looks into a murky past with new investigation into killing of former PM Aldo Moro in 1978

Conspiracy theories swirled around then premier Giulio Andreotti - who died earlier this year - for opposing any sort of negotiation with the kidnappers

Mourners lay flowers and pay their respects to Aldo Moro upon his assassination in 1978 (Getty Images)

Roman magistrates are set to reopen investigations into the kidnap and killing 35 years ago of Italy’s former prime minister Aldo Moro by the Red Brigades, it was reported today.

The new probe into the most shocking of all Italy’s murky post-war political killings, will follow a succession of claims and questions about a crime that many believe was never satisfactorily explained nor properly investigated, even though six terrorists were jailed for their roles.

Allegations by ex-magistrate Ferdinando Imposimato, in particular, are thought to have prompted the willingness to re-open investigations, according to the Adkronos news agency.

The body of Mr Moro, the then president of the centrist Christian Democrats party, was found on May 9, 1978 in the boot of a Renault 4 in central Rome 55 days after he was seized by leftist terrorists.

La Repubblica newspaper noted today that despite four trials, it still had not been established where Mr Moro had been held captive or how many terrorists participated in his kidnapping, during which his five bodyguards were shot dead.

Evidence has continued to emerge that key tip-offs on Red Brigades hideouts were either ignored or fatally delayed in the course of the original investigation.

It has been reported that when the name Gradoli came up, the police descended on a village of that name in the countryside near Viterbo. But they ignored calls to check an apartment in Via Gradoli in Rome, which had been denounced as suspicious by the neighbours. The flat held a large quantity of evidence left by two of Moro’s kidnappers.

The wave of criticism aimed at the then Christian Democrat premier Giulio Andreotti for opposing any sort of negotiation with the kidnappers, added to the web of conspiracy theories. Mr Andreotti was later found guilty but eventually cleared on appeal of involvement in the 1979 killing of the investigative reporter Carmine Pecorelli who had claimed the premier had plotted to ensure Mr Moro did not return alive.

Seven-time premier Andreotti will not be able to help with a new probe. He died earlier this year – taking numerous state secrets with him to the grave.

Some pundits believe that Mr Moro’s plan to bring political stability to Italy by forming a grand coalition between his Christian Democrats and the Italy Communist Party marked his card — not only with the more conservative members of his own party but also with the US, which was said to be nervous about the possibility of communist participation in the government of a major Nato country.