Silverio Sica, lawyer for Monsignor Nunzio Scarano, said his client is accused of fraud, corruption and other charges stemming from the plot, which never got off the ground.
Mr Sica said that Scarano was a middleman in the operation. Friends asked him to intervene with a broker, Giovanni Carenzio, to return 20 million euro they had given him to invest.
Mr Sica said Scarano persuaded Carenzio to return the money, and an Italian secret service agent, Mario Zito, went to Switzerland to return it on board an Italian government aircraft.
He said the plot failed because Carenzio reneged. Carenzio and Zito have also been arrested