LONDON — Investigators were conducting further tests Wednesday in a bid to shed light on the death of Eva Rausing, one of Britain’s richest women, whose body was found in her west London home.

Her husband, Hans Kristian Rausing, has been arrested in connection with her death, which police are treating as unexplained.

U.S.-born Eva Rausing, 48, and her husband were wealthy philanthropists who have both waged a long battle against drug addiction. They were arrested on drug charges in 2008 after Eva Rausing was caught trying to smuggle crack cocaine and heroin into the U.S. Embassy in London in her handbag.

Hans Kristian Rausing, 49, is an heir to the TetraPak fortune his father built as a globally successful manufacturer of laminated cardboard drink containers.

Police found Eva Rausing dead at her multimillion-pound (dollar) London home on Monday. Initial post-mortem examinations Tuesday failed to establish a formal cause of her death.

The Metropolitan Police said officers arrested a 49-year-old man Monday in connection with the case. Police did not release the man’s name but offered details of the arrest in response to a question about Hans Kristian Rausing.