Rosalia Messina Denaro was arrested in 2023 on suspicions that she played a key role in the mob led by her brother.

The 69-year-old, also the wife of jailed mafioso Filippo Guttadauro, unintentionally helped police locate her fugitive brother, thanks to a scribbled note she had hidden in the hollow rail of a chair at her residence.

The note also revealed key details about his health condition.

Matteo Messina Denaro was one of the most ruthless bosses in Cosa Nostra, the real-life Sicilian crime syndicate depicted in "The Godfather" movies.

Investigators had been combing the Sicilian countryside for the mafia boss for years, searching for hideouts and wiretapping members of his family and his friends.

It was his decision to seek treatment for his cancer that led to his arrest in January 2023, when he visited a health clinic in Palermo.

He was captured in January 2023 and died at the inmates' ward of L'Aquila hospital a few months later.

Rosalia, Denaro's confidente and "alter-ego", was the only family member to know about her brother's cancer diagnosis, before he passed at L'Aquila prison's hospital aged 61.

Investigators believed Rosalia played a major operational role in the merciless Cosa Nostra, particularly in the last few years of her brother's run.

She was suspected of managing the clan's finances and the so-called pizzini network -- messages scrawled on pieces of paper to secure communications between the mobster and his gang members.

Rosalia is the mother of Lorenza Guttadauro, a lawyer who defended her mob boss uncle upon his arrest.

Matteo Messina Denaro was convicted of involvement in the murder of anti-mafia judges Giovanni Falcone and Paolo Borsellino in 1992 and in deadly bombings in Rome, Florence and Milan in 1993.

One of his six life sentences was for the kidnapping and subsequent murder of the 12-year-old son of a witness in the Falcone case.

He disappeared in the summer of 1993 and spent the next 30 years on the run as the Italian state cracked down on the Sicilian mob.

He remained at the top of Italy's most-wanted list and increasingly became a figure of legend.