[8] According to Alessandro Silj, three political events transformed him from a radical to an activist: two bloody demonstrations at Trento and a massacre by police of farm labourers in 1968.
Embittered by his expulsion from the radical Red Line faction of Lavoro Politico in August 1969, Curcio decided to drop out of Trento and forget his degree, even though he already had passed his final examinations.
Prior to transferring his bases of activities to Milan, Curcio married, in a mixed (Catholic-Waldensian) ceremony, Margherita (Mara) Cagol, a Trentine sociology major, fellow radical, and daughter of a pent and worker group.
[9] A more militant faction of the CPM, led by Curcio and Cagol, splintered off in 1967 and formed the Red Brigades, which was intended to participate politically while also conducting clandestine military operations.
However, after getting arrested in February 1971 for occupying a vacant house, the Curcios and the most militant members of the Proletarian Left went completely underground and organized the Red Brigades and spent the next three years, from 1972 to 1975, engaging in a series of bombings and kidnappings of prominent figures.
[11] Four months later, a shootout occurred at a safe house between the Red Brigades and the Carabinieri forces, resulting in Cagol being shot twice and eventually dying.
[16] In 1990, while still incarcerated, Curcio started a publishing company, along with Steffano Petrella and Nicola Valentino, called Sensibili alle Foglie, or Sensitive to the Leaves.