ROME — Italy has handed a Bible belonging to the former godfather of the Sicilian mafia to the Federal Bureau of Investigation in the hope that it may provide the key to a secret code that he used to communicate with his henchmen.

The Bible, full of notes marking particular sections, was one of five found in the Corleone lair of Bernardo Provenzano, 73, when he was arrested in April after 43 years on the run.

After his arrest, he asked to be allowed to keep the holy book with him in jail.

He has repeatedly asked for it back and was quoted as saying the Bible needed “not only to be read but also to be understood” — a comment which increased the suspicions of Italian investigators.

“Certain words in the Bible were associated with numbers in the scheme he used in some of his most important messages,” one police source told ANSA, the Italian news agency.

However, after six months studying the Bible, the investigating judge, Giuseppe Pignatone, has called in the FBI.

The book will be scrutinized by the organization’s Cryptanalysis and Racketeering Records unit, which also helps decipher terrorist communications. “This is an initiative which is part of normal collaboration between investigators,” Judge Pignatone said.

Provenzano was a compulsive typist, and amongst his belongings, police found excerpts of the Bible typed on sheets of paper, especially excerpts from the Book of Revelation.

One note contained Revelation 17, chapters eight and nine: “The beast that thou sawest was, and is not; and shall ascend out of the bottomless pit, and go into perdition; and they that dwell on the earth shall wonder, whose names were not written in the book of life from the foundation of the world, when they behold the beast that was, and is not, and yet is.”

The former mafia boss also made constant use of his Olivetti typewriter, producing hundreds of notes, many of which have already been decoded. These have led to several arrests, including one raid in which the heads of 16 mafia families were taken into custody.

Many of the earlier notes were deciphered with the help of one of Provenzano’s right-hand men, Antonio Giuffre, who turned informer after his arrest in 2002.

One was written in the form of the Julius Caesar cipher, which was originally used by the Roman emperor to send commands to the battlefield. The classic Caesar cipher moves all letters three places along the alphabet, so A becomes D. Provenzano’s version also assigned a number to each letter, so A becomes four and B becomes five.

Provenzano abandoned this code after Giuffre’s arrest, and this is when investigators believe that he turned to a biblical code. Since his imprisonment, he has been given a clean copy of the Bible, which he reads every day, annotating and underscoring.