BEIJING — At first it seemed to be nothing more than a routine case of counterfeiting in a country where faking it has become an industry.

In mid-2004, managers at the Tokyo headquarters of the Japanese electronics giant NEC started receiving reports that pirated keyboards and blank CD and DVD discs bearing the company's brand were on sale in retail outlets in Beijing and Hong Kong. So like many other manufacturers combating intellectual property thieves in China, the company hired an investigator to track down the pirates.

After two years and thousands of hours of investigation in conjunction with law enforcement agencies in China, Taiwan and Japan, the company said it had uncovered something far more ambitious than clandestine workshops turning out inferior copies of NEC products.

The pirates were faking the entire company.

Evidence seized in raids on 18 factories and warehouses in China and Taiwan over the past year showed that the counterfeiters had set up what amounted to a parallel NEC brand with links to a network of more than 50 electronics factories in mainland China, Hong Kong and Taiwan.