Tetra Pak billionaire Hans Kristian Rausing has been arrested on suspicion of the murder of his wife Eva Rausing, an inquest heard yesterday.

Police are still waiting to quiz Hans Kristian Rausing, 49, after interviews were suspended on Tuesday so he could be treated for alcohol withdrawal.

Yesterday Hans Kristian Rausing remained in a secure medical facility for treatment and is not fit to be questioned.

Hans Kristian Rausing was first arrested on alleged drugs charges and then later re-arrested on suspicion of murder when his wife’s body was found.

Eva Rausing may have been dead for up to a week before her corpse was discovered.

Hans Kristian Rausing has a large legal team at the inquest, which opened today, headed by legal heavyweight and 7/7 barrister Neil Saunders QC.

Detective Inspector Sharon Marman told Westminster Coroner’s Court yesterday: “We have not yet been in a position to interview Mr Rausing. He has been arrested on suspicion of her murder and we await notification of when he would be fit to be interviewed by police.”

Outlining the facts of the case, she added: “On Monday July 9 this year police had the occasion to stop Hans Rausing driving a car in Wandsworth.

“The officer suspected that the driver was under the influence of drugs or alcohol.

“As a result he was arrested and his car was searched.

“Within the car a small amount of drugs were found and he was taken back to Wandsworth police station.

“An authority was granted to search his home address. During the course of the search officers found the apparently lifeless body of a female in one of the bedrooms.

“That female has been identified as Eva Louise Rausing.”

Eva Rausing may have been dead for up to a week before her corpse was discovered

The court was told Eva Rausing’s father Thomas Kemeny supplied identifying details to the coroner.

Deputy coroner Shirley Radcliffe will review the case at a private hearing in October.

It is thought police are investigating how long Eva Rausing was dead before she was found dead in her home in Cadogan Place, Chelsea, west London. It is thought it could have been up to a week.

Police have been questioning members of staff at their Cadogan Place home and reviewing CCTV tapes in efforts to establish when she was last seen alive.

The couple’s drug addiction has been well documented over the years and recent photos appeared to show the pair in a fragile state.

In 2008 they were investigated by police over drugs but the prosecution was formally discontinued.

Hans Kristian Rausing with drugs offences after police found crack cocaine, cocaine and heroin during a search of his home.

After lengthy discussions between his legal team and prosecutors, he accepted a conditional police caution instead.

The couple was arrested in April that year after Eva Rausing was caught with drugs as she tried to enter the US Embassy in London.

Court documents revealed that Eva Rausing, then 44, was carrying about 10 g of crack cocaine, 2.5 g of heroin and 2.35 g of diethylpropion, a banned stimulant and appetite suppressant.

A further drugs stash – 220 mg of diazepam, used to treat anxiety – was also found in her Renault Clio car.

The couple’s townhouse was subsequently searched. Officers found 5.63 g of crack cocaine, 2.9 g of heroin and almost 52 g of cocaine.

The conditional cautions, administered by a senior local officer, meant the couple admitted possessing the drugs.

Yesterday mother of tragic Eva Rausing, 48, has revealed her daughter flew home from a drugs rehabilitation centre in the United States in the days before her death after her husband failed to join her as planned.

Nancy Kemeny believes her daughter – who had a pacemaker after having a heart valve replaced – died from heart problems triggered by the flight to London.

She said Eva Rausing had come home to try to persuade her husband, Hans Kristian, an heir to the $7.2 billion Tetra Pak drinks carton fortune, to join her for treatment.

And, in an emotional interview, Nancy Kemeny also claimed her son-in-law had been “cleared” by police of involvement in the death.

Scotland Yard officers are waiting to question Hans Kristian Rausing, who is receiving treatment at a secure medical facility, about his wife’s death.

They also need to find out if, as has been suggested, he lived in their $112 million Belgravia mansion for three or four days while her body was in the house.

The fabulously rich couple are said to have existed in virtual squalor in just two rooms of the house as they battled long-term drug problems.

Eva Rausing’s body was found in an upstairs bedroom on Monday when police carried out a search after her husband was arrested in possession of Class A drugs while driving erratically in South London.

A post-mortem examination failed to discover the cause of death. Police are awaiting the results of toxicology and other tests.

Shortly before her death, Eva Rausing had been at a rehabilitation centre in California – the couple had actually met some 20 years earlier at a clinic in the UK – and was due to be joined by her husband.

Nancy Kemeny, whose husband Tom is a Pepsi executive, said: “They were going to go to America, both were going to go.

“Eva was there, she didn’t hear from him, she got worried, she came back home to get him to go back with her. Unfortunately, I think the flying did something with her heart.

“She’d never gone back to the doctor after the valve had been replaced as she was supposed to. She just didn’t go.

“I think it was this flying back and forth from California to London and back again that may have cost her.”

She also said Eva Rausing had a strong influence over his wife.

“She was with us at Christmas, which was great,” she said.

“It was good, very nice. All the family together, well not Hans, he didn’t come. We waited for him every day.”

She said Eva Rausing didn’t stay very long because she returned to her husband.

“I last spoke to my daughter at Christmas. I don’t text and I don’t know how to email. The last we heard was May 3 when she texted my husband.

“She said something about them getting ready to go back to California. Things were starting to take a more positive turn. We had high hopes.”

Wearing a navy blue trouser suit with a black designer handbag and carrying a plastic bag full of British newspapers, Nancy Kemeny said there was no news of when the body would be released but her daughter would “probably” be buried in South Carolina.

“We’re going to have to speak to her husband and he’s in a hospital,” she added.

Asked if she had already spoken to Hans Kristian Rausing, she said: “No. I’d like to.”

She indicated there was no rift between them. Hans Kristian Rausing is said to have been “devoted” to his wife.

Police are examining CCTV footage to track the couple’s movements as well as those of anyone entering or leaving the Cadogan Place house where they had lived for 13 years.

Their bank records are also being looked at and detectives, assisted by specialists, are studying what are described as Eva Rausing’s “long and extremely complicated medical records” for clues as to what led to the death.

The coroner will open the inquest into the death at Westminster Coroners’ Court today.

Scotland Yard would not comment yesterday on whether Class A drugs were found at the house.

Detectives are investigating a theory that Hans Kristian Rausing may have turned to drugs for “comfort or escape” after his wife’s death.

They are trying to trace a dealer in the Wandsworth area of South London.

College friends of Eva Rausing said yesterday they had been worried about her “reckless” lifestyle even as a student in California in the Eighties.

Maths teacher Lola Muldrew, who still lives in California and was part of the graduating class of 1986, said: “She was kind of scattered, somewhat reckless, but she had this wonderfully warm heart and engaging spirit.”

Socialite Liz Brewer, a friend of Eva Rausing, said: “I think the problem with Eva and her husband is that a lot of the time they were in denial about the drugs they were taking.

“For that reason they would not listen when people tried to bring up the subject and tackle it. The whole thing is tragic.”