Born in St. Louis, United States, the son of Italian and British immigrants, Amerigo Dumini moved to Italy and in 1913 he joined the army renouncing his US citizenship. During the First World War he was an assault trooper and was severely wounded and decorated. Then he became active in the Fascio of Florence organized by supporters of Benito Mussolini, taking pride in being referred to as "Sicario del Duce". He participated in the Sarzana incident on 21 July 1921, leading a column of 300 "squadristi" to Sarzana with demands for the liberation of Renato Ricci. Ricci and other fascists had been arrested following armed confrontation with the Arditi del Popolo, an antifascist organization created in 1921 by the anarchist Argo Secondari as an offshoot of the "Arditi" movement. In 1924 Dumini entered the ranks of Ceka, the secret police which Mussolini based on the SovietCheka. Shortly thereafter, on 10 June, he headed the group that carried out the killing of Giacomo Matteotti, possibly on the orders of Cesare Rossi, to whom he was assistant at the time. Following the political murder, he was abandoned by the fascist leadership, with the exception of Roberto Farinacci, who defended him during his trial. While Farinacci declared himself "honored" by the task, he could not prevent Dumini from receiving a five-year prison sentence, of which he only served eleven months, benefiting from an amnesty ordered by Mussolini. Once out of jail, he tried his hand at blackmailing the fascist leadership, trying to obtain rewards and the payment of his legal fees. Ostentatiously, he sought a meeting with Mussolini at the Italian Council of Ministers. He justified his entitlement with the words "I am here in order to wash Matteotti's blood off my hands". Arrested, he was put on trial for "offending Il Duce" and sentenced to eight years in prison—substantially more than for the previous crime. Freed in 1927, Amerigo Dumini left for Italian Somaliland, having been awarded a large state pension. Apparently, he was still viewed as troublesome, since he was detained and interned on the Tremiti Islands. Meanwhile, he warned General Emilio De Bono that he had filed a manuscript detailing Matteotti's murder with notaries in Texas. This claim led to his release and an increase in pension to as much as 50,000 lire. He left for the Italian colony of Libya, where his pension was further increased by 2,500 lire. He remained in the region for more than a decade and was captured by the British Army at Derna during the North African Campaign of World War II. Sentenced to death as a spy, he was hit by 17 bullets from a firing squad and still managed to remain alive, escaping to safety in Tunisia during the night. As Dumini returned to Italy, he was received with astonishment and offered yet another generous pension. He went into business as a transporter and bought a villa in a residential area of Florence. With the 1943 fall of fascism in southern Italy, he joined the German-backed Italian Social Republic. After the Allied occupation of that region, Dumini was arrested in Bologna and placed on trial for Matteotti's murder. He was given a life sentence, but spent no more than eight years in prison and, following more than a decade in quiet retirement, died at the age of 73 at Rome as the result of a domestic accident. In the Florestano Vancini's film The Assassination of Matteotti, Dumini is played by Umberto Orsini.
