A 50-year-old Romanian woman killed her Italian partner at their apartment in the northern city of Modena early on Friday, stabbing him at least 10 times before calling police.
Local news reports named the victim as 60-year-old company director Claudio Palladino.
Police were interrogating the Romanian woman over Palladino's murder, which is believed to have taken place between 5am and 6am.
Palladino was unable to defend himself or escape the frenzied attack during which neighbours said they heard screams coming from his third-floor apartment.
The couple was described by neighbours as "quiet".
The woman was formerly a carer for Palladino's elderly parents, regional daily Il Resto del Carlino reported on its website.
