Denise Cosco, who bravely testified against her father in the notorious mafia murder of her mother, is believed to have taken her own life. Ms Cosco, 35, was found critically injured on Sunday and later died in a Rome hospital.
Her mother, Lea Garofalo, was murdered in 2009 after becoming a state witness against the 'Ndrangheta clan in southern Italy. Ms Cosco, like her mother, had lived under state protection with a new identity for many years.
Prosecutors have launched an investigation into Ms Cosco's death to determine if there was any incitement to suicide, and her phone has been seized for analysis. Her father and three accomplices are serving life sentences for her mother's murder.
Enza Rando, a senator and anti-mafia lawyer who represented Ms Cosco, described her death as "a profound wound for the entire country". Francesca Rispoli, co-president of the anti-mafia organisation Libera, said the death highlights the ongoing struggle for those who break with organised crime.