Matteo Messina Denaro: Coded note led to Italy mafia boss arrest

A coded note hidden inside a chair leg helped lead to the arrest of Italy's most-wanted Mafia boss Matteo Messina Denaro, a warrant shows.

Police found the note during a covert operation at his sister Rosalia's house - one month before his arrest in the Sicilian capital Palermo in January.

Rosalia Messina Denaro was also arrested in Sicily on Friday.

Her brother, 60, spent 30 years on the run and is believed to have evaded justice with help from family.

He is alleged to be a boss of the notorious Cosa Nostra Mafia and was tried and sentenced to life in prison in absentia in 2002 of a string of murders.

More than 100 members of the armed forces were involved in his arrest.

Rosalia Messina Denaro, 67, also known as Rosetta, was herself detained in Sicily on mafia membership charges on Friday, with the Carabinieri - Italian police - releasing a 57-page arrest warrant detailing some of the circumstances which led to her brother's earlier arrest.

The warrant reveals that police found a note inside the leg of an aluminium chair in Rosalia's home in the town of Castelvetrano, in the west of the island, while trying to plant a listening device inside during an operation in December.

Officers photographed the note, which initially seemed like a jumble of words, signs and letters, and replaced it where it was found.

The note was in fact a pizzino - a small piece of paper written in code used by Messina Denaro to communicate with his relatives and affiliates.

Analysis showed it documented a man's struggle with colon cancer, with police focusing their attention on Messina Denaro after verifying that no other family members had similar cancer diagnoses.

The "historic result of the capture... originated from a note, imprudently kept, albeit hidden, by Rosetta", a judge wrote in the warrant.

She is alleged to have played a major role in her mafia family, acting as treasurer, with police saying she communicated with her brother using the code name "Fragolone", or "big strawberry".

The warrant described Rosalia as a woman with "origins and traditions all inspired by an orthodox and rock-hard mafia culture".

The warrant says she is under investigation for being part of the mafia organisation and committing crimes through her membership, helping her brother escape numerous jail sentences, helping him continue in his role as boss of the organisation, and making sure other members of the organisation could communicate with him while he was hiding from the authorities.