The body of Gianmario Roveraro, 70, had been chopped into pieces and hidden in a hut beneath a motorway bridge about 18 miles (30km) from Parma.

The gruesome discovery made sensational headlines in Italy, by chance drawing together two enduring elements of national life: a mysterious financial scandal and the influence of the Church.

Police said that three men had been arrested and charged with Signor Roveraro’s kidnap and murder. But a bizarrely limited confession by the alleged ringleader opened the way for a flood of speculation.

Signor Roveraro, a former Italian Olympic pole-vaulter, had been questioned in an inquiry into the collapse and fraudulent bankruptcy of the food and dairy conglomerate Parmalat, which is based in Parma. In 2003 Parmalat collapsed with €14 billion of debt — Europe’s largest corporate failure.

Signor Roveraro, who had helped Parmalat to list its shares on the stockmarket a decade ago, was last seen on July 5 at a meeting in Milan of the secretive organisation Opus Dei. Italian media reported that he was closely linked with the arch-conservative movement. Some reports said Signor Roveraro was a “supernumerary” or member of Opus Dei. The organisation never confirms individual membership.

Police have made no linkage between his disappearance and Opus Dei.

The speed of the arrests suggested that police had already followed leads concerned with his financial activities.

Noted for his reserve and discretion, Signor Roveraro once said in a rare statement about his involvement with Opus Dei that it was was “not concerned with finance - finance is not Catholic or masonic, it is just finance".

Initial reports said that Signor Roveraro’s corpse had been burnt, but police later said it had deteriorated badly in the heatwave and had been in an advanced state of decomposition when found.

The chief of the police squad that found the body, Luciano Garofano, said: “We are dealing here with a particularly savage murder.”

The alleged ringleader of those arrested is Filippo Botteri, 43, described as a former financial consultant from Parma who allegedly had had business dealings with Signor Roveraro.

Police said that he had confessed to the kidnap and murder but had refused to reveal a motive. He had told investigators he had suffered a memory loss, adding: “Don’t ask me any more questions, I don’t remember a thing”. Police said that the kidnappers appeared to have intended to murder Signor Roveraro from the start given that credible ransom note had been received.

In Dan Brown’s bestselling novel The Da Vinci Code, Opus Dei is portrayed as a ruthless organisation whose members practise corporal mortification and which is prepared to kill to keep its secrets. Opus Dei has vigorously denied this as ludicrous, and has denounced both the book and the film.

The news magazine Panorama yesterday headlined its account “The Roveraro Code”, saying the case involved “rivers of money, opaque interests and shady figures”.

Signor Roveraro was the founder of Akros Finanziaria, a financial services group. Alberto Nobili and Guido Salvini, the magistrates leading the inquiry, said that they were also looking into his “interests” in companies registered in Lugano and London and the recent collapse of an Austrian “high risk” investment firm that he had helped to set up.

On the day of his disappearance Signor Roveraro who had three grown-up children, told his wife Silvana he would be back at his Milan flat in the evening. Instead he telephoned to say he was abroad, in a “German speaking country”, and she would “soon have news”.

Alarmed by this “unusual behaviour”, Signora Roveraro contacted the Carabinieri, who began an investigation. His business colleagues said they later received a “suspicious request” from him by fax, purportedly from Switzerland, asking them to release a million euros.

Police said they were investigating whether the kidnap gang had used “sophisticated computer technology” to make it appear that both the phone call and the money request had come from abroad when in fact the murdered banker had “never left Parma”.

Pippo Corigliano, spokesman for Opus Dei in Italy, said: “We are close to the family at this time and we respect their grief. We are praying for Gianmario, whom God will surely reward for his goodness and kindness.” He added “We were friends for a long time, he was a person of great refinement”.

The case has echoes of the death of Roberto Calvi, the Vatican-linked Milanese financier founded dead under Blackfriars Bridge in London in 1982 after his bank collapsed in a fraud scandal. His death was initially ruled to be suicide, but a murder inquiry was later opened and five people with Mafia links are on trial in Rome accused of conspiring to kill him.

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