The Italian regime was clearly guilty of war crimes (mustard gas in Abyssinia), crimes against humanity (concentration camps in the Balkans, massacres of Abyssinian and Libyan civilians) and crimes against peace, yet none were ever put on trial. This is in stark contrast to other Axis nations, such as Finland, Hungary, Bulgaria and Romania, where all together thousands of suspected war criminals were put on trial. albeit with a low number of convictions. The one thing these countries all have in common is that they fell under Soviet occupation. Would there have been similar war crime trials in Italy had it been under Soviet occupation? Why were the Western Allies so uninterested in prosecuting Italian war criminals?
It's not the case that there were no trials, though there could have been more. Italy itself prosecuted war crimes. Marshal Rodolfo Graziani , guilty of atrocities in Abyssinia, was sentenced to nineteen years (served only two), though for crimes in Italy, not Africa. Lower down the food chain, there was Pietro Caruso, questura at Rome who aided the SS in the massacre of Italian partisans at the Ardeatine caves. He was found guilty and executed. (See my book Tiber, pg 243 for an expanded discussion and a bit of unjustice.)
In the case of the Balkans, the incoming communist regime simply expelled the local Italians and confiscated their goods. Mario Roatta, who did terrible things in Croatia, was on the run for years and tried in absentia for his acts.
Then there's the fact that the Western Allies were concerned that the Communists might take over Italy, which also argued for a lighter touch than there might otherwise have employed. (Finland did not fall under Soviet occupation.) Politics complicated much in this area, but there was some justice served up after the war..