Over 7,400 suspected pirated textbooks valued at HK$530,000 have been seized in raids on two bookshops and a warehouse in the New Territories. They were managed by a syndicate which supplied the books to schools and parents. Four suspects, aged 52 to 62, were arrested - two of them syndicate directors and the other two staff - in the raids on Thursday of Ching Fung Book Store branches in Yuen Long and Tuen Mun, and a warehouse in Tuen Mun. They supplied books to 35 primary schools in the city, the Customs and Excise Department said yesterday. More than 90 titles - published by Oxford University Press, Educational Publishing House and Pearson Education Asia - were seized, said Lee Hon-wah, head of customs' intellectual property bureau. A number of legitimate copies of the books were found in the raids. Officers believed the syndicate sourced a certain number of genuine copies from the copyright owners, then mixed them with the pirated versions and supplied them to schools and parents in a bid to avoid detection and boost profits. Customs began investigating the syndicate after it received complaints from parents of inferior-quality textbooks. Officers initially seized more than 200 suspected pirate copies of books awaiting collection by parents at two primary schools. The copyright owners confirmed that the books were not genuine copies. An Oxford spokeswoman said it was evaluating the loss and would assist those affected. The other publishers could not be reached for comment. Educational Publishers Association spokeswoman Dr Sharon Wong Yin-yue said: "The bookstores have been working with many publishers for a long time … We never expected to see this." She put the publishers' combined losses from the operation at up to HK$10 million.