Calabresi was born on 14 November 1937 into a middle-class Roman family. His father was a wine and oil merchant. He attended the classical secondary schoolSan Leone Magno and graduated from university with a law degree in 1964 with a thesis on the Sicilian Mafia. He chose to enter the police over a career as an attorney and was sent to Milan, where he was assigned to investigate anarchist groups. On 12 December 1969, a bomb exploded in the Milan office of the National Agricultural Bank in Piazza Fontana. 17 people were killed and 88 others wounded. Among those interrogated as suspects was anarchist railway worker Giuseppe Pinelli. On the night of 15 December, Pinelli died from a fall from a fourth floor window of the police headquarters. Theories of what caused Pinelli's fall included murder, suicide, and an accident due to loss of consciousness. On 3 July 1970 judicial authorities closed the case as an accidental death. A second inquiry in 1975 confirmed this by ruling Pinelli's death due to an "active illness". The 1975tribunal further found that Calabresi was not in the room at the time of Pinelli's death. However, elements of the far left did not accept the determination.
Despite being exonerated by the institutions of the Italian state, the far-left Lotta Continua accused Calabresi of being responsible for the death of Pinelli. For two years he was the focus of a media campaign, led in part by the weekly L'Espresso, that held him responsible for Pinelli's death. Calabresi was shot in the street and murdered in Milan on 17 May 1972 on his way to work. He was deputy leader of the political section of the Milan office of the Italian State Police when he was murdered. The judge of the first trial was the President of the criminal court of Milan, Carlo Biotti. Lotta Continua disbanded in 1976. In 1988, a former member of Lotta Continua, Leonardo Marino, confessed to having participated in the murder of Calabresi. In May 1990Adriano Sofri, leader of Lotta Continua, along with members Giorgio Pietrostefani and Ovidio Bompressi, were convicted and sentenced to 22 years in prison. Leonardo Marino was sentenced to 11 years. On 14 May 2004, President Carlo Azeglio Ciampi awarded the gold medal for civil merit to the memory of Luigi Calabresi. Calabresi is a servant of God as ordered by Pope Paul VI.
