PASSAU, Germany, Dec. 5, 2008 -- State prosecutors have indicted 43-year-old Swiss national Helg Sgarbi for allegedly blackmailing BMW heiress Susanne Klatten, Germany's richest woman.

In August 2007, Klatten, 46, a married mother of three teenagers, fell for Sgarbi, whom she had met at the famous spa retreat Lanserhof, a hangout for the rich and famous in Tirol, Austria, Munich's daily newspaper Sueddeutsche Zeitung reported today.

Little did she know that her lover reportedly had an Italian accomplice named Ernano Barretta, 63, who was secretly filming their meetings from a hotel room next door and planning to use the footage to blackmail her.

The publicity-shy heiress filed charges against her former lover in January, according to Munich state prosecution spokesman Anton Winkler.

The incident, however, was revealed in November when the German media discovered the story.

Sgarbi is alleged to have not only blackmailed her but also other wealthy German, Austrian and Swiss women.

The affair between Klatten and Sgarbi reportedly lasted for about two months in the summer of 2007, during which time Sgarbi persuaded Klatten to pay almost $10 million with a tale about having caused a tragic car accident that involved the child of a mafia boss, who was demanding a payoff, according to prosecutors.

But the suspect demanded millions more and threatened to publish some photos that were taken during their affair, if Klatten did not pay more, according to media reports. The heiress instead abruptly ended the relationship.

She hired private detectives to monitor telephone calls in which the suspect allegedly threatened to publicly release some intimate videotapes unless she paid up.

In January Klatten led him to believe that she was going to hand over the money at an Autobahn parking lot near Innsbruck, Austria, but instead she sent the police. They arrested Sgarbi, prosecutors said.

He's been in Munich's Stadelheim jail since January and is now awaiting trial.

Barretta, his reported accomplice, was arrested by police in Italy and is in jail in his hometown of Pescara. He's accused by Italian authorities of being the mastermind of the scheme to extort money from wealthy German women.

Sabatino Ciprietti, his lawyer, told ABC News there is no hard evidence against his client and insisted "the whole affair is a case of international gossip."

Ciprietti said all the fuss and the Italian investigation were consequences of the prominence of the accuser.

Meanwhile the prosecutor in Pescara is moving forward and has requested that Barretta's case go to trial. The indictment hearing is expected to begin in the spring.

The BMW heiress is not the only rich woman alleged to have been blackmailed, but she is certainly the most prominent.

Germany's Wealthiest Woman

She's Germany's wealthiest woman. She ranks 55th on the 2008 Forbes Magazine list of world billionaires with a net worth of $13.2 billion that includes a 12.5 percent stake in BMW.

She is the daughter of industrial tycoon Herbert Quandt, who transformed a nearly bankrupt BMW into the automobile giant it is today.

Klatten's family reportedly lives in Munich's artsy Schwabing district.

Klatten used to be so media shy that some called her reclusive. There is hardly any video of her and her family -- the media here have been using the same archive photos of her over and over again.

By filing charges Klatten revealed her identity and for the first time she gave an exclusive interview to The Financial Times Deutschland where she was quoted as saying, "You are a victim and you must protect yourself. I am pressing charges on behalf of all women in my family and in the name of many more women."

She has not talked to any other media and is not giving any interviews.

Joerg Appelhans, her spokesman, issued a statement to ABC News: "Once Ms. Klatten realized that the relationship with Mr. S. was based on the criminal intent to betray her and extort money, she was determined to take action. She was fully aware that by pressing charges, she would face the unpleasant consequences of opening her private life to public scrutiny."

Because the trial is imminent, Appelhans declined to comment on details about the affair that have emerged in press reports.

It is not clear whether Klatten or any of the women involved will have to appear in person once the trial begins.

Ann Wise contributed to this report