The paper revealed that Michelle Young had hired Simon Sutton, described as "a controversial fraud investigator".
The Mail says Young was particularly paranoid about enquiries on his wealth. He had stated that the hunt for the money was driving him crazy, and he had even demanded to be confined for treatment under the Mental Health Act.
In one of Britain's biggest divorce cases, $4, according to the Daily Mail.
The case has seen several twists although Scotland Yard has said the death is not considered suspicious.
According to a friend, $4.In the divorce trial, Young had repeatedly claimed he was not able to pay the maintenance fee to his former wife and daughters, although the judge in charge convicted him for contempt of court for hiding his assets from the inquiry.
In 2013, Young spent six months in prison for that sentence.
Although Young's friends $4, Scotland Yard is under pressure to open an inquiry after $4 have also died in mysterious circumstances in the last four years.
The group included the exiled oligarch Boris Berezovsky, who was found hanging in his Surrey house in 2013.