Floral tributes have been left outside the London home of Eva Rausing following the discovery of her body on Tuesday.
ITV News understands that Eva's husband Hans Kristian Rausing, the heir to the Tetra Pak drinks carton empire, is continuing to receive medical treatment after being arrested in connection with her death.
Mr Rausing was arrested after Eva's body was found at the couple's home in Cadogan Place, Chelsea.
Mr Rausing, who stands to inherit a billion-pound fortune from his father's business, was taken into custody at a south London police station but has since been moved to a "medical facility", police said.
Scotland Yard would not confirm the name of the suspect, but said a 49-year-old man was arrested in south London on Monday morning on suspicion of possession of drugs.
Police are treating Mr Rausing's death as "unexplained".