Tetra Pak heir Hans Kristian Rausing has been arrested on suspicion of murdering his wife Eva, according to reports.
The 48-year-old was found dead at the couple's London mansion on Monday.
The Daily Mail reports that so far - a post mortem has failed to discover the cause of her death, but it is thought she may have been dead for up to a week before her corpse was discovered.
An inquest into Mrs Rausing's death opened in London today.
Police discovered the “lifeless body” of millionairess Mrs Rausing after they arrested her husband over drugs earlier this week, the hearing was told.
Mrs Rausing, one of Britain’s richest women, was found dead in a bedroom of the opulent Cadogan Place house in London’s Chelsea which she shared with Mr Rausing.
A post-mortem examination proved inconclusive and further test results are awaited.
There was no comment on how long Mrs Rausing’s body had lain in the five-storey Georgian townhouse.
According to reports it may have been there for several days.