Heir Not Fit for Questioning in Wife's Death Hans Rausing, the billionaire heir who was arrested in connection with his American wife's death, is receiving treatment for drug and alcohol withdrawal, and has yet to be questioned by police, according to today's inquest into her death. The death of his wife, Eva Rausing, 48, whose body was found in the couple's London home, is still being investigated as an "unexplained death," even though Rausing has been arrested on suspicion of his wife's murder, a Metropolitan Police spokesperson told ABCNews.com. On Monday, Hans Kristian Rausing was arrested for driving erratically. Upon searching his car, police found drugs, which prompted them to search the home he shared with his wife in the London's Belgravia neighborhood, according to a police spokesperson. Officers found the lifeless body of Eva Rausing in an upstairs bedroom at their home. The heiress, who was a friend of Prince Charles, may have been dead for more than a week, according to reports. A postmortem held Tuesday at Westminster Mortuary was inconclusive. Authorities said they were waiting on toxicology results to determine if the heiress, who had a history of drug addiction, had died of an overdose. Hans Rausing, who is Swedish, is an heir to the Tetra Pak food packaging empire. Together, Hans and Eva Rausing were well-known as a billionaire power couple who donated generously to addiction-related charities but also secretly battled the same demons that brought them together 25 years ago in an American rehab clinic, where they first met. She was also a patron of the Mentor U.K. charity, a group that works to keep children away from alcohol and drugs. The Rausings' appetite for drugs was not publicly known until their arrests in 2008. Officers then searched the couple's home, where they found crack, heroin and cocaine. The Rausings were issued a formal caution and the charges were dropped. I am very sorry for the upset I have caused. I have made a grave error, and consider myself to have taken a wrong turn in the course of my life," Rausing told the BBC in 2008. Rausing alluded to her struggle to fight addiction on her Myspace page. In a posting, which appears to be from 2007, she wrote that she was looking for ways to use her time constructively. I fell back into the same hole as before and have been there for nearly seven years. I once read that I would have seven bad years (I don't normally believe in hocus-pocus horoscopes), but so far it has been right," Rausing wrote. I'm hoping for seven good years starting 2007. A private hearing to further review the case has been scheduled for Oct. 5.