Dalian police have cracked an operation selling illegal pornographic software that grossed more than 140 million yuan ($21.17 million), authorities said on Tuesday.

The network security department of Dalian, Liaoning province, found in February that the operation in Beijing hired a suspect, surnamed Lyu, to design an app that would supply users with pornographic material.

According to police, hackers were also recruited to place links promoting the app on the websites of legal and unwitting companies.

The cumulative operating revenue from selling the software reached 140 million yuan, with an illegal profit of more than 20 million yuan.

Eight people were detained in cooperation with the Beijing Public Security Bureau. Police also seized 11 computers and 25 mobile phones, and froze more than 24 million yuan in criminal proceeds.

In an ongoing campaign against cybercrime, Liaoning police have taken action against 71 cases of hacking, detained 151 suspects, and collected more than 10 billion pieces of stolen information.