Pietro, who is from Italy, is an elementary particle physicist working in Bologna as senior researcher for the Italian Institute for Nuclear Physics (INFN).
He graduated with a degree in Physics from Turin University and holds a Ph.D. from the same University. He is currently a member of one of the experimental collaborations collecting data at the Large Hadron Collider, the main accelerator facility operating at CERN, the European Laboratory for Particle Physics based in Geneva. During his career, Pietro's research fields moved from neutrino physics and cosmic rays to the study of relativistic heavy ion collisions.

Pietro has been a member of Amnesty International since the late 1980s and has closely followed the evolution of organization's mission during the last twenty years. In the 1990s he joined the board of Amnesty International Italy, where he served as Vice-Chair. At the international level, he was a member of the Standing Committee on Research and Action from 2001 to 2003, and in 2004 joined the board of the Amnesty International European Union Association, of which he became Chair in 2006.

He was elected to the IEC in August 2007. On the IEC he was the lead on particular projects reviewing Amnesty's work on and in Europe and developing AI's international growth strategy, chairing the IEC Strategy Committee. He was elected IEC Chair in September 2011.