After 15 years of lies, cover-ups and mysterious suicides, an answer might be close at hand to one of the most enduring riddles of post-war Italy: the cause of the destruction of an Italian airliner over the island of Ustica, near Sicily, in June 1980.
According to documents seized from the retired head of the counter-espionage service, it seems the DC-9 was caught in the wrong place during an attempt by Nato fighters to blast Colonel Muammar Gaddafi out of the skies with a missile.
The papers sequestered by the judiciary from Demetrio Cogliandro detail how French and US jets launched an operation to kill the Libyan leader but panicked when they were counter-attacked by escorting MiGs. When the civilian airliner came into range, a French Mirage fired without first checking its identity, killing all 81 people on board.
It is not the first time the possibility of a missile attack has been raised but never has such detailed information leaked from such a highly- placed source. General Cogliandro's dossier describes how one of the MiGs was also shot down and how five US P-3 Orions vainly scoured the wild terrain of Calabria to trace its fuselage. He describes disinformation spread about the MiG once it was found three weeks later and pressure applied on doctors who examined the pilot's body.
He also names the prime minister of the time, Francesco Cossiga, as being responsible for concealing the truth for so long. Mr Cossiga, who was later president, has never given a full account of the affair, claiming only that he was "shafted" somewhere along the line.
An investigating magistrate, Rosario Priore, says he is taking the dossier seriously, as it seems to have been prepared for formal distribution, perhaps as a memo to the head of Italy's secret-service agency. But it is unclear who General Cogliandro's sources were, why he compiled his report and why it took so long to surface.
So reticent did the general prove in interrogation before the discovery of his papers that he has been investigated for alleged obstruction of justice. For some of Mr Cossiga's most faithful supporters, that has been enough to discredit the missile theory and suggest, as they have for several years, that the DC-9 was blown up by a terrorist bomb.
The parliamentary commission dealing with Italy's many high-profile disasters is unlikely to kiss off the evidence quite so quickly and is expected to summon Mr Cossiga for questioning. France and the US never commented on the affair, while Colonel Gaddafi has been as equivocal as ever.