Guido Salvini started investigating events relating to Italy 's strategy of tension , which have involved a NATO stay-behind anti-communist network known as Gladio , in July 1988 . After 463 interrogations , the investigations produced 60,000 pages . He indicted in 1998 David Carrett , officer of the US Navy , on charges of political and military espionage as well as participation in the 1969 Piazza Fontana bombing . He also indicted Sergio Minetto , Italian official member of Gladio , and '' pentito '' Carlo Digilio , indicted in the Piazza Fontana investigation . The neofascists had decided to kill Mariano Rumor , on retaliation against his decision not to proclaim the state of emergency following the Piazza Fontana bombing &mdash; which , according to neo-fascist Vincenzo Vinciguerra , was one of the main objectives of this bombing
Piazza Fontana bombing
Piazza Fontana bombing
Guido Salvini (judge)