During the German occupation of Italy in World War II he briefly enrolled in Junio Valerio Borghese's private fascist militia Decima Flottiglia MAS, forging contacts which would later come in handy during his career as a journalist.
Described by La Repubblica as an "anti-communist but not a fascist", he soon gravitated towards the ruling Christian Democrats (Democrazia Cristiana; DC), becoming associated in particular with the party's administrative secretary, Egidio Carenini.
Initially writing for Nuovo Mondo d'Oggi, a political journal with such a reputation for muckraking that it was closed down by the Ministry of the Interior, in 1968 Pecorelli founded his own press agency, Osservatore Politico (OP).
OP later became a weekly magazine specializing in political scandals, and by the late 1970s, it had published many first-hand stories that Pecorelli was able to obtain through his numerous contacts in the government, including those in the secret services.
Pecorelli publicly acknowledged that his best pieces were often those which had not been published due to agreements with the subjects involved, most of whom preferred to pay hefty sums of money to ensure his silence.
In a cryptic article published in May 1978, Pecorelli drew a connection between Operation Gladio (NATO's 'stay-behind' anti-communist organization, whose existence was publicly acknowledged by Prime Minister Giulio Andreotti in October 1990) and Moro's death.
[1] Moreover, at the end of September 1978, as recounted by his sister Rosita, Pecorelli handed over a dossier with names of several "unfaithful" prelates to Pope John Paul I a few hours before his mysterious death.
[7] The case was circumstantial and based on the word of Mafia turncoat Tommaso Buscetta, who had not originally mentioned the allegation about Andreotti when interviewed by Giovanni Falcone and had recanted it by the time of the trial.
[8][9] On 6 April 1993, Mafia turncoat Tommaso Buscetta told Palermo prosecutors that he had learnt from his boss Gaetano Badalamenti that Pecorelli's murder had been carried out in the interest of Andreotti.