The trial of a computer expert said to be behind internet scams which earned him £1.6m, has started hearing from alleged victims.
Peter Francis-Macrae, 23, of St Neots, Cambs, denies threatening to kill and blackmail at Peterborough Crown Court.
He also denies transferring criminal property, threatening to destroy or damage property and fraudulent trading.
The prosecution claim he threatened to kill police and trading standards officers investigating his activities.
The court heard earlier that Mr Francis-Macrae is alleged to have offered thousands of e-mail and website names he was not registered to sell.
Businessman John Hunt, of Southampton, Hampshire, said he became suspicious and contacted investigators after he tried to buy website domain names from Mr Francis-Macrae.
Rupert Mayo, prosecuting, has told jurors Mr Francis-Macrae had misused his talents to get very rich over a five-year period, enjoying a lavish lifestyle including designer clothes and helicopter flying lessons.
He said Mr Francis-Macrae sent unsolicited e-mails to thousands of people offering to sell them registered names for e-mails and websites.
But be was never registered to sell such names and had been perpetrating a scam which netted hundreds of thousands of pounds a week, it was claimed.
The case continues.