Rausing, the son of Tetra Pak tycoon Hans Rausing and heir to a £5.4billion fortune, was arrested after being caught with drugs in South London yesterday.
Police then went to search his home and discovered the body of his wife in an upstairs bedroom at the five-storey Georgian townhouse.
An investigation is under way to determine the cause of her death which police have described as ‘unexplained’.
Rausing, who was re-arrested in connection with the death, remained in custody this evening at a South London police station.
Four years ago Mrs Rausing was caught trying to smuggle heroin and crack into a function at the American Embassy in London.
When police searched the couple’s home they found more crack and heroin – and £2,000 worth of cocaine.MBUTA NANGA" NDO MAMBO YA UTAJIRI "RUWA MANGI"
But they escaped trial as when the case came to court prosecutors announced they had been handed conditional cautions instead.
After the hearing Mr Rausing’s family said they ‘hope with all our hearts’ that the couple can ‘overcome their addiction’ and pledged to help.
Mr Rausing’s father, Hans, was one of the founders of the packaging giant Tetra Laval which created the modern milk carton.
He moved to the UK in the 1980s to avoid punitive Swedish taxes and now lives on a 900-acre estate in East Sussex. He is listed as one of Britain’s richest men.
The couple moved into their five-storey mansion in Cadogan Terrace after selling another property near-by for £12.65m six years ago.
They also have an 11-bedroomed beachside mansion in Barbados, one of the biggest on the island, and a large apartment on The World, a cruise ship for passengers who need to be offshore for tax-avoidance purposes.
A Metropolitan Police spokesman said:‘On Monday a 49-year-old man was arrested on suspicion of possession of drugs. Following a subsequent search of an address in Cadogan Place SW1 a body was found.
‘The death is being treated as unexplained. A post mortem was conducted at 1pm today at Westminster mortuary.
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