Family Of China-Detained Hong Kong British Consulate Staffer Tells UK 'They're Worried Sick'

A current employee of the British consulate in Hong Kong that was reported missing for nearly two weeks has reportedly been detained in mainland China. The country's foreign affairs ministry confirmed the information on Wednesday, fueling speculations that Hong Kongese anti-government protestors can now be prosecuted in China.

Simon Cheng, a 28-year-old Hong Kong citizen, has been placed on administrative detention for 15 days according to China's Ministry of Foreign Affairs spokesman Geng Shuang. Cheng works as a trade and investment officer for the British Consulate General in HK.

Geng clarified that Cheng "is a Hong Kong citizen," adding that he's Chinese and the arrest is "purely an internal Chinese affair." The Shenzhen police detained the British consulate employee for meddling with China's Security Administration Punishment Law.

Mainland China often uses the law as a preparatory measure that allows the police to investigate a suspect before deciding to prosecute. Annie Li, Cheng's girlfriend, said that her partner traveled from Hong Kong to Shenzen on August 8 in his role as the British consulate's trade officer.

Cheng currently works at the consulate's Scottish Development International investment agency. A branch that promotes trade and goodwill between Scotland and other countries, the job often requires him to go to mainland China for work.

According to Li, Cheng messaged her on the night of August 8, just before crossing the border to Hong Kong. She has not heard from him since, adding that Britain must do something to rescue her detained boyfriend. In correspondence with CNN, she said that if Chen "hadn't been given that assignment, he wouldn't have obliged to go to Shenzhen."

On Wednesday, a spokesperson for the British Consulate-General in Hong Kong told CNN that legal help is available for employees detained for reasons associated with their employment. "However, we need to authenticate the facts before we can decide what action is appropriate."

In an announcement released on Tuesday, the British Consulate-General stated that they were "extremely concerned" of Cheng's disappearance and detention in Shenzen.

Cheng's family also showed signs of desperation. On his Facebook account, the 28-year-old's family said that they "feel very helpless, and are worried sick about Simon." They added that they're hoping that "Simon can return to Hong Kong as soon as possible."

On her last correspondence with his partner, Li told CNN that he messaged her to say that he was on his way to Hong Kong via a high-speed train. Cheng later told Li that he was about to pass through the border then he stopped communicating.

Li said that Cheng is a permanent resident in Hong Kong traveling with a mainland travel permit. She added that Cheng also has a British National Overseas (BNO) passport. The document allows citizens of Hong Kong consular assistance from the UK but is not equal to UK citizenship.

China does not acknowledge dual nationality for any Chinese national, indicating that it does not recognize BNO passports like the one issued for Cheng. The British consulate employee's detention comes as Hong Kong nears its 12th weekend of mass pro-democracy demonstrations aimed at the mainland.