Eva Rausing's body lay undiscovered for a week at her Belgravia home, say police

Eva Rausing, the wife of an heir to the Tetra Pak fortune, may have lay dead for up to a week in a bedroom at the couple's £50m central London home, it emerged yesterday.

Scotland Yard confirmed that the time of death for the mother-of-four was part of its ongoing investigation. A post-mortem examination failed to establish an immediate cause of death despite an apparent overdose, lending weight to the theory that she had been dead for some time prior to the discovery of her body on Monday.

Her husband, Hans Kristian Rausing, 49, remains in an unnamed south London hospital where he is understood to be likely to be require a lengthy period of treatment.

He was arrested on Monday in connection with his wife's death after being found driving erratically in south London, and a subsequent search led to the discovery of her body in their five-storey Belgravia house. It emerged yesterday that American-born Mrs Rausing, who is the daughter of a wealthy Pepsi Cola executive and struggled for many years with health and addiction problems, had alluded to her drug abuse on the MySpace website.

Writing in 2007, she said: "I don't work but probably should. Or at least think of a constructive way of using my life. I fell back into the same hole as before and have been there for nearly seven years."