The Fascist regime was born out of a political assassination, that of the Socialist parliamentarian Giacomo Matteotti in 1924. Matteotti had criticised fascism bitterly in the parliament before being kidnapped and murdered by fascists. It is still an open question whether Benito Mussolini himself knew and authorised the assassination of Matteotti. He handled the situation very well (for turning Italy into the dictatorship he wanted it to be, that is). At this stage, he did not enjoy full control over squadristi, the quasi-fascist paramilitary groups. Anti-fascist groups protested the murder of Matteotti through various methods, including threatening the Mussolini government with general strike and withdrawal from the parliament. Communists assassinated fascist parliamentarian Armando Casalini some days later in retaliation. Some fascists and squadristi demanded further action, the anti-fascists wanted the killers of Matteotti punished by the King, and somehow Mussolini got himself a dictatorship out of this wobble!

This kind of assassinations was not that rare in Italy, especially from the aftermath of the WW1 to the full control of Mussolini throughout the country. Another example is Aurelio Padovani. Padovani was a leading fascist official from Napoli. He was a more left-wing, revolutionary fascist, if you like. He found himself in trouble with Mussolini and died in suspicious circumstances in 1926. He had made peace with Mussolini before his death, though he never held any office in the Party again. Contemporaries had suspicions about his deaths and so do some historians today.

Outside Italy, the fascist regime was decisively more violent. In Ethiopia, in Spain (during the Civil War) and in Greece, the war crimes were numerous and included mass civilian murders. Not the subtle political assassination you might find in Italy, but thousands of civilians in Addis Ababa were killed in retaliation for an attempted assassination of Rodolfo Graziani in 1937. The massacre is now known as Yekatit 12. Italians also had concentration camps in Ethiopia and did not hesitate to use chemical weapons.

Despite all these, the fascist regime was not completely bent on terrorising the whole of its population. As Paul Corner puts it (p. 75):

Unlike in Nazi Germany, therefore, where the party controlled the police and where Nazi police units could operate with relative impunity under the cover of the infamous protective custody regulations, people in Italy (with one or two notable exceptions) did not just disappear after being driven away in the large black car.

In short, the fascist regime was neither your typical liberal democratic government with relatively few extralegal actions, nor was it as "rogue" as the Soviet or the Nazi regime, in general. That, as far as I know, is the consensus among historians today. There are some disagreeements, of course. I will cite one such work by Michael Ebner against this way of thinking below, one that I have not had the chance to read yet but have heard a bit about. I am quite new to the field of Italian history myself, even though I am a professional historian of the same period elsewhere, and I would much prefer leading you to sources than making mere assertions!

Sources:

Paul Corner, The Fascist Party and Popular Opinion in Mussolini's Italy (Oxford: 2012).

Michael Ebner, Ordinary Violence in Mussolini’s Italy (Cambridge, 2010).

Storia d'Italia nel periodo fascista, ed. by Luigi Salvatorelli and Giovanni Mira, 6th edn. (Torino, 1656-1968).

Angelo del Boca, Italiani, brava gente?: Un mito duro a morire (Vicenza, 2005).