Image caption The twins allegedly claimed Marl could pick stocks on the verge of soaring in value by up to 400%

Twin brothers from England face US civil charges for allegedly defrauding investors out of $1.2m (£745,000) through a bogus stock-picking robot.

Alexander and Thomas Hunter, of Whitley Bay, North Tyneside, were aged 16 when, in 2007, they devised the scheme of the robot, dubbed Marl, say US officials.

The Securities and Exchange Commission said the stocks "picked" were actually firms that paid the twins hefty fees.

The Hunters allegedly snared about 75,000 investors, mostly in the US.

In November, Newcastle Crown Court ordered Alexander Hunter to pay back nearly $1m after he admitted providing unregulated financial advice. He was given a suspended 12-month prison sentence.

'Goldman Sachs algorithm'

According to an affadavit filed in a New York federal court on Friday, investors paid $47 for newsletters listing Marl's stock picks and $97 for a "home version" of the software.

"The longer Marl is allowed to run on a computer... The More Advanced He Becomes!" one of the brothers' websites said.

The home version was simply a program that grabbed ticker symbols fed in by the Hunters, who reportedly live with their parents in Whitley Bay.

The twins collected an additional $1.9m from companies that paid to appear in the newsletters and in the software program, according to the US court document.

In one example given by the Securities and Exchange Commission, Marl picked stock in 2008 for a music publishing company called UOMO Media, doubling its share price to 69 cents, and then again a year later, driving it to $1.06. UOMO has not traded above a penny since September 2010.

The twins claimed Marl had a track record of detecting cheap stocks whose prices were on the verge of soaring by 200-400%.

Marl was a supposed combination of the names of its phoney creators, Michael Cohen and Carl Williamson. The Hunters claimed that "Michael Cohen" had developed a Goldman Sachs trading algorithm that reaped billions in profits.

Officials are asking the court to block the Hunters, now 20 or 21, from the securities industry and return money to investors. They are also seeking further financial penalties.

Eric Bruce, a lawyer for the Hunters, did not respond to requests for comment on Friday, reports Reuters news agency.