Police in Beijing have raided a factory that produced and exported more than 41,000 fake iPhones worth a whopping 120 million yuan ($19 million) this year alone.

Police arrested nine people, including a married couple who authorities believe are the leaders of the counterfeiting operation, after they carried out a raid two months ago on the factory, which was running under the guise of a gadget maintenance company, according to Reuters.

The factory, located in the suburbs of Beijing, employed hundreds of workers, who have produced the fake smartphones on six assembly lines since 2011, according to police.

The replicas were manufactured using discarded cellphone parts obtained from overseas and accessories purchased from Shenzhen, a city known for electronics manufacturing. The finished products were then sold abroad. Beijing police seized more than 1,400 fake phones during the raid, according to CNN.

Beijing police said they conducted the investigation following a tip-off from U.S. authorities, who had seized some of the fake mobile phones.

The raid took place amid an official Chinese crackdown on counterfeit goods, with authorities encouraging companies to trademark their products. China has also agreed to work in conjunction with the U.S. authorities to curtail the trade of counterfeit products between the two countries, BBC News reported.