NEW DELHI—When the chief executive of helicopter maker AgustaWestland spotted executives from rival Sikorsky Aircraft Corp. across the dining room in the Taj Mahal Hotel, he sent over a bottle of wine with a note attached. "You can't always win," it said, according to Italian authorities.

Giuseppe Orsi, then AgustaWestland's CEO, had learned earlier that day in 2010 that his helicopter company had beaten Sikorsky to win a $734 million contract to supply a dozen helicopters to the Indian government.

His exultation proved premature. Mr. Orsi and a colleague at AgustaWestland, a unit of Italy's Finmeccanica SpA, were arrested by Italian police last year and subsequently charged with international bribery and falsifying invoices in connection with the deal.

Italian prosecutors allege that Mr. Orsi, who rose to become head of Finmeccanica in 2011 before resigning last year, orchestrated a plan to pay tens of millions of dollars to Indian officials, including the former top officer in the Indian air force, to win the helicopter-supply competition. He is now standing trial outside of Milan, and a verdict is expected early next month.

Mr. Orsi, 68 years old, denies wrongdoing and said in court the allegations against him were concocted by adversaries within Finmeccanica, a major arms manufacturer that is partially owned by the Italian government. A spokesman for Mr. Orsi says the note he sent to the Sikorsky executives was congenial, and that the wording was different than described by Italian authorities in Mr. Orsi's arrest warrant.