In 1965, he was one of the lecturers at a conference about revolutionary war held at the Hotel "Parco dei Principi" in Rome, which was organized by Fascist politician Pino Rauti and his Ordine Nuovo organization. He was later questioned by the court about the Piazza Fontana bombing. As his lecture was thought to have been devised and used to plan a general "strategy of tension" to destabilize Italian democratic system, and due to one of his students, Delfo Zorzi, being enquired for material responsibility. However inquiries proved that he was not involved in any way.