LONDON — The husband of Eva Rausing, one of Britain's richest women, has been arrested on suspicion of murder in the death of his wife, even though no cause of death has been established, police said Friday.

The body of 48-year-old Eva was found Monday at the couple's London home. The Metropolitan Police say detectives are treating the death as "unexplained," and Hans Kristian Rausing has not been charged.

However, Detective Inspector Sharon Marman told a preliminary inquest hearing Friday that "Mr. Rausing ... has been arrested on suspicion of her murder."

He is receiving medical treatment and has not yet been questioned by detectives.

Marman said a post-mortem examination failed to establish the cause of Eva Rausing's death and police were awaiting the results of further tests. It was unclear how long that might take.

Hans Kristian Rausing is an heir to the Tetra Pak drinks-carton fortune. He and his U.S.-born wife lived in a luxury townhouse in a leafy London square, donated millions to addiction charities and had a long history of drug use.

They were arrested in 2008 after Eva Rausing was caught trying to smuggle crack cocaine and heroin into the U.S. Embassy in London in her handbag. The charges were dropped when the couple admitted guilt and accepted a police reprimand.

CORRECTION: A previously published version of this article incorrectly identified the Eva Rausing's husband as his family's company, Tetra Pak.

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  • This photo of Nov. 26, 1996 shows Eva Rausing, right, and her husband Hans Kristian Rausing at Winfield House, London, the residence of the US ambassador to the UK attending the Glamour America Fashion Show and lunch. One of Britain's richest women, American-born Eva Rausing, was found dead in her west London home and a man was arrested in connection with the case, British police say, adding that an autopsy had failed to uncover a formal cause of death. Rausing, 48, was the wife of Hans Kristian Rausing, heir to the TetraPak fortune his father built by creating a successful manufacturer of laminated cardboard drink containers. (AP Photo/Alan Davidson/The Picture Library Ltd)

  • Taken with a fisheye lens, a photo shows a police officer standing guard outside the home of Britain's richest women, right, American-born Eva Rausing who was found dead in her home in Belgravia, London, Wednesday, July 11, 2012. (AP Photo/Sang Tan)

  • This photo taken from PA video shows police outside a house in Cadogan Place, Chelsea after the body of Eva Rausing, a member of the family behind the Tetra-Pak drinks carton empire and one of the richest women in Britain was found, Tuesday July 10, 2012. (AP Photo/PA Video, Leanne Rinne)

  • This photo taken from PA video shows police outside a house in Cadogan Place, Chelsea after the body of Eva Rausing, a member of the family behind the Tetra-Pak drinks carton empire and one of the richest women in Britain was found, Tuesday July 10, 2012.(AP Photo/PA Video, Leanne Rinne)

  • A Police investigation officer, sheltering from the rain with a folder, arrives at the home of Britain's richest women, American-born Eva Rausing who was found dead in her home in Belgravia, London, Wednesday, July 11, 2012. (AP Photo/Sang Tan)

  • Police tape lines the outside of the house of Eva Rausing in Knightsbridge on July 10, 2012 in London, England. It has been reported that the body of Mrs Rausing, the wife of Tetra Pak heir Hans Kristian Rausing, was found here yesterday. (Photo by Peter Macdiarmid/Getty Images)