Simon Cheng, a 28-year-old who works as a trade and investment officer for the British Consulate General Hong Kong, has been put in administrative detention for 15 days, China’s Ministry of Foreign Affairs spokesman Geng Shuang said Wednesday.
“The person is not a British citizen. He is a Hong Kong citizen, so he is a Chinese citizen and this is a purely Chinese internal affair,” Geng said.
Cheng messaged Li on the night of August 8, just before he was about to go cross the border into Hong Kong, Li told CNN. She has not heard from him since.
“Simon has signed a contract with the British government,” she told CNN. “If he hadn’t been given that assignment, he wouldn’t have needed to go to Shenzhen. Britain must take the responsibility in rescuing Simon.”
The British Consulate-General in Hong Kong on Tuesday addressed local media reports detailing Cheng’s disappearance. “We are extremely concerned by reports that a member of our team has been detained returning to Hong Kong from Shenzhen,” a spokesperson said in an email.
“We are providing support to his family and seeking further information from authorities in Guangdong province and Hong Kong,” the spokesperson added.
The British Embassy in Beijing put out an identical statement.
China does not recognize dual nationality for any Chinese national, meaning it does not recognize BNO passports.
Cheng’s disappearance comes as Hong Kong approaches its 12th weekend of mass pro-democracy protests. Travelers told CNN that security at the border between Hong Kong and China had increased since the mass protests began in June.
A Hong Kong man who recently crossed back to the city from China told CNN that border police appeared to be picking people at random to be subjected to extra searches. The man — who asked not to be named — said police scrolled through the photos on his phone.
In a statement posted online Wednesday morning, Cheng’s family reiterated that Cheng had been in Shenzhen on a “business trip.”
The family said they had not received any notice of administrative detention, which is supposed to be sent out within 24 hours of a person’s detention. “We simply have never received any documentation confirming that Simon has been formally detained by the authorities,” the statement said.
In the statement, the family said that a lawyer representing them had gone to three detention centers in Shenzhen, but was unable to find Cheng. Police stations in Shenzhen and Guangzhou, and the Guangzhou Railway Public Security Bureau, also had no information on his whereabouts.
Authorities in both Hong Kong and mainland China — which operates under a separate legal system from Hong Kong — have released few details of the case. On Tuesday, Hong Kong Police Senior Superintendent Kong Wing-cheung confirmed that they had received a missing person report on August 9. The Hong Kong Immigration Department also confirmed it had received a request for assistance from Cheng’s family and was providing them with advice and assistance.
CNN has reached out to the Guangdong Provincial Public Security Bureau and the Shenzhen City Public Secruity Bureau.
CNN’s Matt Rivers and James Griffiths contributed to this report.