What is the importance of the bank in Milan in the play, Accidental Death of an Anarchist?

In the play's back-story (events before the story actually begins), a bank in Milan was bombed and several people were killed. The Anarchist of the play's title was accused by the police of being involved, and was in the process of being interrogated when he died. Late in the play the journalist formulates the theory that the bombing was actually staged by the authorities in an attempt to discredit the Anarchist and his friends.