They are two people whose lives could not be more different from yours and mine. He, for example, received for his 50th birthday a 10-foot sailing dinghy made of chocolate. She, in her massive New York apartment, hired 17 people to dress in red hotpants and tote umbrellas while singing "It's Raining Men" at a Valentine's Day party.

They, in short, are not us. But who are these people whose lives and travails now threaten to further soil the reputation of former president Bill Clinton - and to shake the Democratic Party to its core?

Mr Clinton granted a pardon in January to Marc Rich, a 66-year-old commodities trader living in Switzerland who was charged in 1983 with tax evasion to the tune of $48 million. He was also charged with fraud, and with doing illegal oil deals with Iran. Mr Rich and his partner, Pincus Green, paid $200 million in fines, but fled the US rather than go through a criminal jury trial.

Mr Rich's ex-wife Denise contributed more than $1.5 million to Democratic Party causes over the last few years. She also wrote to then president Clinton asking for the pardon for her ex-husband and, some say, spoke to him about the case.

Both a Congressional investigation and a criminal inquiry launched by the US federal prosecutor in New York are now focusing on Ms Rich. Her phone records and personal bank statements will be subpoenaed and examined. If it can be proved that her contributions to the Democrats, including some $450,000 to the Clinton Library, had any link to Mr Rich in Switzerland, there could be possible charges of money laundering and campaign finance law irregularities.

For now, the focus in on Ms Rich. In testimony before Congress she invoked the Fifth Amendment, the US constitutional provision against self-incrimination. Congress is now considering whether to grant her immunity from prosecution, but people from the federal prosecutor's office are opposing this. Some in the feds office believe Ms Rich may have laundered money: moreover, they want to hold the threat of prosecution over her head to force her to tell all she knows about the pardons procedure.

Ms Rich is routinely described in the press as a "songwriter-socialite", but she is much more than that. She was one of two daughters of two Holocaust survivors, Emil Eisenberg (88) and his wife Gery, now deceased. The couple founded a very successful shoe company. Denise was raised in Massachusetts.

Her father set her up in a blind date with Marc Rich in 1966. He was born in Antwerp, fleeing Belgium with his parents just before the Nazi invasion. He had risen from the mailroom to become a top trader at Philipp Brothers brokerage.

They married six months after that blind date, in October 1966. The brokerage firm moved the family to Madrid, where they lived for 14 years. Denise gave birth to three daughters.

During the 1970s and 1980s, according to prosecutors, Mr Rich made more than $100 million illegally, disregarding price controls on oil and funnelling profits to Swiss banks.

Instead of standing trial when charges were filed, the family fled in 1983 to Zug, Switzerland, which does not recognise foreign charges for tax evasion.

By 1985, Denise was finding her own voice as a songwriter. She wrote "Frankie" which became a major hit for the group Sister Sledge. Later she wrote "Free Yourself" for Chaka Khan, "Love is on the Way" for Celine Dion, and other songs for Aretha Franklin and Patti Labelle. Sources in the industry describe her as financially very successful.

After learning of an extramarital affair Mr Rich was having, Ms Rich returned to the US in 1991. With the purchase of her lavish Fifth Avenue duplex, she became a major social figure in New York.

The parties have been legendary: 300 helium balloons, celebrities such as Michael Douglas and Catherine ZetaJones, Goldie Hawn, Ivana Trump munching on goat's cheese ravioli and ahi tuna. One famous photo shows her giggling on her couch with Mikhail Gorbachev at her side. She also garnered three Grammy award nominations. And she began a friendship with Bill and Hillary Clinton, eventually becoming a fiercely loyal party supporter.

The year 1996 was devastating for Denise Rich. After 30 years of marriage she and Marc divorced, and he married a woman named Gisela. Perhaps even more devastating was the death of their daughter Gabrielle at 27 of leukemia.

When Gabrielle was diagnosed with the disease, Denise underwent a difficult donation of bone marrow for a transplant to help save her daughter. It didn't work, and Gabrielle, an aspiring actress, died in her mother's arms on September 9th, 1996.

In her letter to Mr Clinton, Ms Rich lamented that Marc Rich was denied the opportunity to see his daughter before she died because of the outstanding charges.

For his part, Mr Rich has been living well, and making even more money in the metal and commodities fields. Over the past 20 years, he has reportedly contributed $70 to $80 million to charities in Israel, which lobbied Mr Clinton hard for the pardon. Avner Azulay, the ex-chief of the Mossad, Israel's spy agency, said he worked hard to gather support for the pardon.

For her part, Ms Rich is now trying to keep an uncharacteristic low profile in Manhattan, shunning the flamboyant parties. An extrovert and feisty woman, she is not even speaking to the media, something unheard of for her. The federal prosecutor, Mary Jo White, is seeking Ms Rich's personal financial records to determine the sources of both her wealth and her political generosity.

This is a political and criminal inquiry that is making many people across the US very nervous.