Oracle chief executive Larry Ellison Wednesday defended his company's decision to hire detectives to investigate two research groups that supported Microsoft during the antitrust trial.

Oracle hired Investigative Group International to probe two research organizations, the Independence Institute and the National Taxpayers Union. The company sought to verify links between Microsoft and the organizations during its antitrust trial--and even tried to buy trash from another research group with close ties to Microsoft. Oracle told Bloomberg News it discovered that the two organizations were misrepresenting themselves as independent advocacy groups when they were in fact funded by Microsoft. Oracle said the company hired the detective agency because the organizations were releasing studies supporting Microsoft during the antitrust trial. The financial ties between the organizations were reported by The Wall Street Journal and The Washington Post. "It's absolutely true we set out to expose Microsoft's covert activities," Oracle chief executive Ellison said during a press conference at Oracle's headquarters in Redwood Shores, Calif., in which the company announced new software products. "I feel very good about what we did."