London (CNN) -- Hans Kristian Rausing, the son of one of the world's wealthiest men, was arrested on suspicion of murder after the body of his American-born wife was found in their home this week, police confirmed Friday.
The 49-year-old was initially arrested Monday on drug charges and then was held "in connection with the death" of Eva Rausing, police said Tuesday.
The new details of his arrest emerged during the inquest into her death, which opened at Westminster Coroner's Court on Friday.
The Metropolitan Police said there is no murder inquiry yet and the death is still being treated as unexplained.
Authorities are awaiting the results of further post-mortem tests, which are not expected for several more days, police said.
An autopsy Tuesday failed to determine the cause of Eva Rausing's death, police said.
Detective Inspector Sharon Marman told the coroner that police had discovered the drugs when they searched Rausing's car after stopping him on suspicion of driving under the influence of alcohol or drugs, the UK's Press Association news agency reported.
They then searched his home address, a mansion in one of London's most expensive neighborhoods.
During that search, officers discovered the "apparently lifeless body of a female in one of the bedrooms," Marman said, according to the news agency.
The suspect has been arrested on suspicion of her murder, "and we await notification of when he will be fit to be interviewed," she said, quoted by the Press Association.
A spokesman for Hans Kristen Rausing, James Henderson, told CNN that nothing had changed in Rausing's position.
"He was arrested on Monday on suspicion of murder. He has not been questioned yet. He has not been charged," he said.
Henderson said Rausing was still receiving medical treatment, and he did not know when he would be questioned.
Police earlier this week declined to name Hans Kristian Rausing as the man who was arrested, but a source familiar with the investigation said the man in custody lived at the address where the body was found.
He is the son of Hans Rausing, who is worth an estimated $10 billion, thanks to the family's connection to Swedish packaging giant Tetra Laval.
CNN's Susannah Palk and Atika Shubert contributed to this report.