The mutilated and decomposing body of Milan banker Gianmario Roveraro was discovered by Italian police on Friday, just outside of Parma, according to Italian news agency ANSA.
His death is a blow to the investigation into the collapse of Parmalat. Police had questioned Roveraro about financial advice he gave the Italian dairy giant in the 1990s, and his involvement in launching the group on the stock market.
Parmalat has been involved in a string of lawsuits with several top banks and financial consultancy firms during the last year, in a dispute over who should share the blame for its downfall in 2003.
Roveraro had been missing since 5 July, after reportedly attending a meeting of Opus Dei, the secretive Catholic group shot to fame by Dan Brown's conspiratorial novel, the Da Vinci Code.
The Italian press has made much of Roveraro's alleged links to Opus Dei. Brown's book, largely rubbished by Catholic Church members, portrays Opus Dei as a sect-like group that would kill to guard its secrets.
However, it appeared Friday that the more familiar motive of a financial dispute may be to blame for the banker's death.
Police have charged three men with kidnapping, one of which was the fellow Parma-based financier Filippo Botteri. News agency ANSA reported that police had discovered Botteri was involved in a dispute with Roveraro over failed investments in Austria.