Question: Marina Petrella  is a former member of the Red Brigades that operated during which an era known as what ?

full_context: Document 1: Patty Hearst: Patricia Campbell "Patty" Hearst (born February 20, 1954), now known as Patricia Hearst Shaw, is the granddaughter of American publishing magnate William Randolph Hearst. She became nationally known for events following her 1974 kidnapping while she was a 19-year-old student living in Berkeley, California. Hearst was abducted by a small left-wing terrorist group with only 20 members known as the Symbionese Liberation Army. After being isolated and threatened with death, she became supportive of their cause, making propaganda announcements for them and taking part in illegal activities.
Document 2: Red Brigades: The Red Brigades (Italian: "Brigate Rosse" ] , often abbreviated "BR") was a left-wing paramilitary organization, based in Italy, responsible for numerous violent incidents, including assassinations, kidnapping and robberies during the so-called "Years of Lead".
Document 3: Alberto Franceschini: Alberto Franceschini (born 26 October 1947) is an Italian former terrorist, a founder and leading member of the Italian left-wing militant organization, the Red Brigades ("Brigate Rosse"), along with Renato Curcio, Margherita Cagol and Mario Moretti.
Document 4: Adriana Faranda: Adriana Faranda (born 7 August 1950) is an Italian former terrorist, who was a member of the Red Brigades during the kidnapping of Aldo Moro.
Document 5: Mario Moretti: Mario Moretti (born 16 January 1946) is an Italian terrorist. A leading member of the Red Brigades in the late 1970s, he was one of the kidnappers of Aldo Moro, president of Italy's largest party, Democrazia Cristiana, and several times premier, in 1978; he later confessed to killing the politician.
Document 6: Renato Curcio: Renato Curcio (] ; born 23 September 1941) is the former leader of the Italian left-wing militant organization, the Red Brigades ("Brigate Rosse").
Document 7: Valerio Morucci: Valerio Morucci (born 22 March 1949) is an Italian former terrorist, who was a member of the Red Brigades and who took part in the kidnapping and assassination of Aldo Moro in 1978.
Document 8: Prima Linea: Prima Linea (Italian, English: "Front Line") was an Italian Marxist–Leninist terrorist group of the late 1970s. It was formed in 1976 by members of hard-line factions within the far left, extra-parliamentary organization "Lotta Continua", which disbanded that year, together with members of "Potere Operaio" and of other far left groups. By 1982 it had carried out more than twenty assassinations.
Document 9: Villa Grimaldi: Villa Grimaldi is considered the most important of DINA’s (Dirección de Inteligencia Nacional, the Chilean secret police) many complexes that were used for the interrogation and torture of political prisoners during the governance of Augusto Pinochet. It is located at Avenida José Arrieta 8200 (now 8401) in Peñalolén, on the outskirts of Santiago, and was in operation from mid-1974 to mid-1978. About 4,500 detainees were brought to Villa Grimaldi during this time, at least 240 of whom "disappeared" or were killed by DINA. It was also the location of the headquarters of the Metropolitan Intelligence Brigade (BIM). The head of Villa Grimaldi during the Pinochet dictatorship, Marcelo Moren Brito, was later convicted of crimes against humanity and sentenced to more than 300 years in prison.
Document 10: Montoneros: Montoneros (Spanish: "Movimiento Peronista Montonero-MPM" ) was an Argentine leftist terrorist and urban guerrilla group, active during the 1960s and 1970s. The name is an allusion to the 19th century cavalry militias, called Montoneras, who fought for the Partido Federal during the Argentine Civil Wars.
Document 11: Dolours Price: Dolours Price (21 June 1951 – 23 January 2013) was, along with her younger sister Marian, a Provisional Irish Republican Army (IRA) volunteer. She was also a political activist who became a staunch critic of Gerry Adams' leadership of Sinn Féin.
Document 12: Alessio Casimirri: Alessio Casimirri (born 1951) is an Italian terrorist and member of the Red Brigades (BR), currently fugitive.
Document 13: Prospero Gallinari: Prospero Gallinari (1 January 1951 – 14 January 2013), also known as "Gallo" (i.e. "rooster"), was an Italian terrorist, a member of the Red Brigades (BR) in the 1970s and 1980s.
Document 14: Esther Norma Arrostito: Esther Norma Arrostito (January 17, 1940 – January 15, 1978) was an Argentine political activist and leftist militant, initially close to communist ideology. In 1970, she became one of the founders of the peronist revolutionary movement Montoneros along with Fernando Abal Medina, who developed a romantic relationship with her. She played a key role in the kidnapping and killing of General Pedro Eugenio Aramburu.
Document 15: Marina Petrella: Marina Petrella (born 23 August 1954) is a former member of the terrorist Italian left wing group the Red Brigades.
ground_truth: Years of Lead