Four employees of a Chinese military industry enterprise were arrested recently for providing information about its products to foreign spies.

In a raid code-named “Mine Sweeping,” the national security agencies in China’s southwestern province of Sichuan captured the four suspects who have been accused of cooperating with overseas intelligence agencies.

They worked in the same enterprise but did not know one another, according to sources from the security agencies.

The four were recruited online by foreign spies through social media apps, the sources said.

One of the suspects, who was only identified by his last name Wen, got in contact with a person nicknamed H on QQ, an extremely popular instant messaging software service developed by the Chinese company Tencent. H turned out to be a spy who wanted Wen to provide information about military products of the enterprises he worked with.

Wen has been accused of providing H with classified information such as the models of products and the volume of production each month.