Swedish billionaire's son arrested after U.S.-born wife found dead

Police stumbled into the mystery Monday, when they arrested Hans Kristian Rausing on drug charges.

A search of his home in one of London's most expensive neighborhoods turned up the body of his wife, Eva, spurring police to arrest him again in connection with the death.

Eva Rausing had struggled with drug addiction for years, an acquaintance said.

"This has been an existing problem for a long time," said Liz Brewer, who knew Rausing through charity and social circles. "I think the whole thing is a complete tragedy."

The case puts the multimillionaire couple squarely back in the headlines four years after they were arrested on charges of possessing cocaine and heroin, according to media reports at the time.

Eva Rausing had tried to smuggle a small amount of crack cocaine and heroin into the U.S. Embassy in London, reports said. She and her husband were arrested when police found more drugs at their house.

The pair, however, avoided prosecution. Since then, they have kept a low profile, Forbes magazine said in its annual rich list report this year.

"It's very clear to us Eva had her own problems with drugs and drugs misuse," the head of an anti-drug organization told CNN Wednesday.

"She knew prevention was important. She knew how hard it was to get off drugs once you are on drugs," said Paul Tuohy, chief executive of Mentor.

Eva Rausing had donated hundreds of thousands of dollars to the charity in the years before her death, Mentor said.

Her husband is the son of Hans Rausing, who is worth an estimated $10 billion, thanks to the family's connection to Swedish packaging giant Tetra Laval.