Taiwanese law enforcement agents searched the offices of four optical storage drive makers on July 3 after chip designer Mediatek alleged that the companies had used its technology without permission, local Chinese-language newspapers reported.

Officials from the Ministry of Justice Investigation Bureau is probing into whether Benq, Behavior Tech Computer (BTC), AOpen and EPO Science and Technology pirated code developed by Mediatek for its CD-R60 chipsets, according to the reports. The allegations come just a week after Mediatek filed a patent infringement suit against VIA Technologies and AOpen for violating two of its US patents.