so here we go, even if I'm afraid you won't find anything romantic in this story...
On December the 12th 1969 a bomb exploded in Milan, causing the death of 17 persons. The police asked to a man called Giuseppe Pinelli, known as an anarchist, to go to the police place to be interrogated and kept him there for a few days without permission. He was completely innocent and finally died falling from a window. Subsequently the policemen stated that Pinelli threw himself out of the window committing suicide, while a large part of public opinion thought that Pinelli was tortured and accidentally fell during a "non-orthodox" interrogation.
The play "Accidental death of an anarchist" is about what happened in this police place, embracing the idea of abuse by police officers. One of these officers, Mr Luigi Calabresi, the highest in degree, was considered responsible of the death of Giuseppe Pinelli by some extremist political groups and murdered three years later.
In 1997 four people were judged resposible of the death of Mr Calabresi, and among these people were Adriano Sofri, who is Daria Bignardi's father-in-law (she is married to his son Luca, a journalist).
Adriano Sofri is widely considered a sensitive intellectual, he has always claimed his innocence and he obtained the support of many intellectuals, politicians and journalists.
I think Daria believes as well that her father-in-law is innocent and appreciated Mika's interest in this old and tragic Italian fact (even if i'm not sure of Mika's full awareness about the political depth of Fo's play) and wanted to acknowledge his deep interest in Italian culture and history.
Obviously this is only a summary and I tried to be as objective as possible, and just for the record Luca Sofri mentioned "TOOL" as one of the best songs of the year back in 2012 in his Vanity Fair column so I think Daria already knew about Mika before the whole X Factor thing