“Of some ‘secret committees’ of the Socialist Party, charged with preparing the revolution, the Italian police was already concerned in 1919. The second congress of the Communist International, in 1920, established that the organization of an illegal party apparatus was an indispensable condition for joining the International. And already in September 1921 the European police agreed to exchange data in the anti-Bolshevik struggle. Police control did not seem to meet with much resistance: in July 1922 the illegal communist apparatus (Office I) was “permeable” at its top, Bruno Fortichiari – he was the Martini of the Moscow meeting in May 1923 – and Giuseppe Berti.
On 29 January 1923 Fortichiari complained to the Center that rumors about him and the clandestine apparatus circulated too much in Milan: security regulations were neglected. On 3 February Bordiga, one of the party leaders, was caught by the police coming out of an illegal office in Via Frattina in Rome, with £2500, just received from the Soviets, and various documents, which he was thinking of securing. Terracini (the Urbani of the Moscow meeting) speaks, in his reports to the International, of a catastrophic blow for the party. After the capture of Bordiga, and in relation to it, the police will in fact arrest over 250 people”.
Massimo Mastrogregori, Comunismo underground e segreto, in «Storiografia», 23, 2019, pp. 241-258.