Nunzio Scarano, who is accused of fraud, corruption and other charges stemming from the plot, which never got off the ground, was arrested in his parish in the outskirts of Rome and taken to the city’s Queen of Heaven prison.
Bishop Scarano is said to be a middleman in the operation, according to his lawyer Silverio Sica.
Friends are said to have asked Bishop Scarano to intervene with a broker, Giovanni Carenzio, to return 20 million euros they had given him to invest.
Mr Sica said Bishop Scarano persuaded Mr Carenzio to return the money, and an Italian secret service agent, Mario Zito, went to Switzerland to bring the money back aboard an Italian government aircraft.
He said the plot failed because Mr Carenzio went back on his promise. Messrs Carenzio and Zito have also been arrested.
Journalist and Vatican expert Franca Giansoldati told Associated Press that the current scandal would lead to reform: “There are several cardinals who even wanted the Vatican bank to close down, and others who want it to become an ethical bank.”
Misuse of care home funds?
Prosecutors in the southern city of Salerno have already placed Monsignor Scarano under investigation over allegations that he used money from wealthy friends intended to fund the construction of a home for the terminally ill, to pay off his own mortgage.
His lawyer, Mr Sica, said Bishop Scarano had wanted to pay off the mortgage in order to sell a property in Salerno and use the proceeds to build the care home.
It has been alleged that Scarano took out a total of 560,000 euros in cash from his account at the Vatican bank – never withdrawing more than 10,000 euros at a time. He is then said to have given the money to friends who paid it back in the form of cheques, which he paid into an Italian bank to repay the mortgage.
Scarano was suspended from his duties as a senior accountant at a financial office of the Vatican when the magistrates in Salerno placed him under investigation.