Petacci had a long-standing relationship with Mussolini while he was married to Rachele Mussolini. Mussolini was twenty-eight years Petacci's senior. Part of their correspondence is still the subject of a dispute with the National Archives, based on privacy.
On 27 April 1945, Mussolini and Petacci were captured by Communist partisans while traveling with a convoy of Italian Social Republic members. On 28 April, she and Mussolini were taken to Mezzegra and shot. On the following day, 29 April, Mussolini's and Petacci's bodies were taken to the Piazzale Loreto in Milan and hung upside down in front of a petrol station. The bodies were photographed as a crowd vented their rage upon them.