American banking heir Matthew Mellon admitted passing on "fake" e-mails to his lawyers ahead of his "acrimonious" divorce battle, a court has heard.
Michael Mellon is one of five men denying a total of 15 charges
The e-mails appeared to show that his wife, Jimmy Choo footwear empire boss Tamara, hid money in an offshore account and was selling the business.
The bogus e-mails were created by private detectives trying to find out how much his estranged wife was worth.
Mr Mellon and four others on trial at Southwark Crown Court deny all charges.
The court heard that Mr Mellon thought his wife might be holding back information and that he had been unable to find out the details through the courts.
When he was interviewed after his arrest in early 2005 it is claimed he told police: "I was simply exercising my right to hire a firm of private investigators."
He allegedly added: "I sort of knew I was riding the border of unethicalness."
Mr Mellon told police that, while he "believed" the documents had not been genuine, he still gave them to his solicitors, the court heard.
Miranda Moore QC, prosecuting, said the 43-year-old tycoon denied knowing the material given to him by private investigators Active Investigation Services (AIS) had been illegally hacked.
The e-mails contained a virus called Trojan designed to record the computer keystrokes made by Mrs Mellon.
The jury heard that she became suspicious and called in her IT manager, which meant AIS started receiving e-mails from the computer specialist instead.
Ms Moore said the hacker made up two e-mails - claiming Mrs Mellon was not being fully honest about her finances - to cover up the plan's lack of success.
Mr Mellon, now divorced and living in Belgravia, central London, denies one count of conspiring to cause unauthorised modification of computer material between 1 July, 2004 and 4 February, 2005.
Also in the dock is ex-policeman Scott Gelsthorpe, 32, from Kettering, Northamptonshire, who helped run AIS, agency employee David Carroll, 58, of Highgate, north London; Daniel Carroll, 36, from Westminster, central London; and Maurice Kennedy, 58, of Barnet, north London.
Mellon's co-accused variously deny 15 counts of conspiracy, alleging fraud, the unauthorised modification and interception of computer material, and criminal damage.
Mellon, heir to a £5bn oil and banking fortune, married Tamara Yeardye in a society wedding at Blenheim Palace in 2000. Mrs Mellon started divorce proceedings in 2004.
The trial was adjourned until Monday.