Luca Traini, 28, embarked on his shooting spree on February 4, following the sordid murder of a young Italian woman allegedly at the hands of Nigerian drug dealers.
Pamela Mastropietro's body was found dismembered and stuffed into suitcases days before Traini's attack.
The two incidents, which occurred at the height of Italy's tense electoral campaign, shook the country and laid bare its deep tensions surrounding immigration.
Pro-migrant demonstrations across Italy condemning the attack were in contrast to an outpouring of support for Traini who received messages of solidarity for his actions and, controversially, no politician paid a visit to his victims in hospital.
Traini was charged with attempted murder and racial hatred.
The former security guard admitted to the shooting but rejected allegations the attack was racially-motivated, insisting he wanted to target drug dealers.
His defence team had provided a psychiatric report which stated that Traini suffered from a personality disorder and that he was not completely aware of his actions at the time of the attack.