ROME — A Vatican official. A private plane. And 20 million euros in cash.

Claiming to have foiled a caper worthy of Hollywood, or at least Cinecittà, the Italian police on Friday arrested a prelate and two others on corruption charges, saying that the priest plotted last summer to help wealthy friends sneak the money, the equivalent of about $26 million, into Italy while evading financial controls.

Along with the prelate, a financial broker and a military police agent deployed to the Italian Secret Service were arrested after an investigation that developed out of a broader three-year inquiry into the Vatican Bank. The case is the latest black mark on the bank, which under Pope Francis and Pope Benedict XVI has been trying to shake its image as a secretive tax and money laundering haven and bring itself into compliance with European norms so it can use the euro.

Rome prosecutors say the three men hired a private plane last July with the intention of bringing the cash into Italy from Locarno, Switzerland. The money was to be carried by the Secret Service agent, Giovanni Maria Zito, who would not be required to declare it at the border. But the scheme fell through, the prosecutors said, as the three began bickering and, eventually, lost their nerve. Cellphones used by the three in arranging the money transfer were later burned, prosecutors said.

The European Union and the United States have served notice in recent years that they will no longer tolerate the wall of secrecy in tax havens like Switzerland, Luxembourg and the Cayman Islands. As a result, major account holders have been growing increasingly nervous.