Eva Rausing, daughter of U.S. businessman Tom Kemeny, led a gilded life marred by drug addiction and had a host of connections with royal patrons of anti-drug charities to which she and her husband, Hans Kristian Rausing, 49, devoted millions from the fortune his Swedish grandfather made from packaging.
Police said on Tuesday they were holding a 49-year-old man in connection with the death of Eva Rausing, who was found dead on Monday in her home in the capital's wealthy Belgravia district. He was also being investigated for drug possession. But they declined to confirm British media reports that he was Hans Kristian Rausing.
Statements from both spouses' parents made no mention of him in expressing sadness, shock and admiration for the mother of his four children, and for her charity work to curb drub abuse.
The couple, who were reported to have met while undergoing rehab in the United States, hit headlines in 2008 when Eva Rausing was found carrying heroin and the "ghetto drug" crack cocaine into the U.S. embassy in London. Charges against her and her husband were later dropped.
Her father-in-law, Hans Rausing, 86, is one of the world's wealthiest men, ranked 88th in the Forbes rich list with a fortune estimated at $10 billion. Based in Britain since quitting high-tax Sweden 30 years ago, he sold his interest in the private Tetra Pak business to his brother in the 1990s.
Police declined to comment on newspaper reports that the mystery of Eva Rausing's death began with her husband's arrest after driving erratically in London on Monday.
When police went to the couple's white-stuccoed townhouse in Cadogan Place they found his wife dead in an upstairs bedroom, several newspapers said, adding that a post mortem on Monday had been inconclusive but that a drug overdose was suspected.
"Eva was a devoted wife for 20 years and mother of four much loved and wonderful children," they said.
"During her short lifetime she made a huge philanthropic impact, supporting a large number of charitable causes, not only financially, but using her own personal experiences. She bravely fought her health issues for many years."
In 2008, after the embassy drugs incident, their daughter told reporters: "I have made a grave error and consider myself to have taken a wrong turn in the course of my life."
She was a patron of the British branch of the Mentor Foundation, a worldwide drug abuse prevention group whose president is Queen Silvia of Sweden, and was also a trustee of a community development charity founded by Britain's Prince Charles, The Prince's Foundation for Building Community.
At another organisation which benefited from the Rausings' generosity, Nick Barton, chief executive of Action on Addiction, said: "Everyone involved with Action on Addiction is devastated to hear the news of Eva Rausing's untimely death.
"Without any desire for public recognition, Eva has, through her wonderfully generous support of this and other charities helped so many people for over 20 years."
Her husband, often referred to as simply Hans K, was born into billions in 1963, as his father, uncle and grandfather were turning their local packaging firm into a global empire with their innovative cardboard bricks. Media reports describe him as having lapsed into drug abuse while travelling in India in his 20s, a young man with vast means and little sense of purpose.
His father Hans Rausing, whose own father founded Tetra Laval in Lund, Sweden, in 1944, also has two daughters with his wife Marit. Praised by, among others, Prince Charles for his philanthropy, Hans Rausing has an honorary British knighthood.
"Hans and Marit Rausing and their family are deeply shocked and saddened to hear of the tragic death of their daughter-in-law Eva Louise Rausing," the family said in a statement. "They ask that their privacy be respected at this sad time."
Police said the man they had detained was receiving medical attention. Officers had sealed off the couple's house in an area, near Sloane Square, which is home to some of Britain's - and increasingly the world's - wealthiest people seeking the lifestyle, relatively low taxes, security and anonymity that London offers.
(Additional reporting by Alastair Macdonald in London and Niklas Pollard in Stockholm; writing by Alastair Macdonald; editing by Mohammad Zargham)