A computer expert working for UBS PaineWebber has been charged with trying to manipulate the stock price of the brokerage's parent company by sabotaging its computer system.

Roger Duronio, 60, of Bogota, hoped to cash in on a resulting drop in the stock value of the parent company, prosecutors said.

Duronio spent just under $22,000 in February and March buying a type of security known as a put option contract, which increases in value as a company's stock price declines, according to the New York Times.

Prosecutors claim he then sent a computer virus to 1,000 of the 1,500 computers used by PaineWebber brokers across the country.

But the plan failed to disrupt work seriously or cause a sharp change in the stock price.

Duronio has pleaded not guilty and his laywers said that the police analysis of his stock trading is out of context.