A man going into the mainland for business reasons was supposedly detained by Shenzhen police because he wore a black T-shirt. And he was released only after pledging he would not join protest action in Hong Kong.
This account came from the man's company after extra security checks at Shenzhen-Hong Kong border points came in on July 24.
The stepped-up measures include more security officers at immigration e-channels and manual counters, with people and their belongings scrutinized going in and out of the mainland.
Social enterprise "Mosi Mosi" posted on its Facebook page that the employee going to Shenzhen for business several days ago "was unexpectedly stopped and searched by mainland police just because he wore black."
Then police checked photographs stored on his phone and chat histories on WeChat and WhatsApp. It was from those sources that officers discovered the man joined an anti-fugitive bill protest on June 16.
"Our employee was only one of the two million who took part in a legal and peaceful rally, but the mainland police seized his mainland travel permit and detained him for six hours until midnight," the post said.
"He had to write a letter of repentance and they even jabbed his finger to collect his DNA after taking a photo of his face."
So the company advised people not to wear black when heading to the mainland and to delete all photos, videos and chat histories relating to politics.
"It's because mainland police can detain you and search your phone simply because they find you suspicious," the company said. "They have no standard to follow. Be careful!"
The post also said the owner of the enterprise went to the mainland a day after the incident and wore a cartoon T-shirt. But he was not detained.
Democratic Party legislators James To Kun-sun said the stop-and-search incident was serious.
"Behavior in Hong Kong should be judged by SAR law," he said on a radio program yesterday, and expressing an opinion through a legal protest is protected by the Basic Law. "But a Hong Kong citizen was judged in the mainland for actions he took in the SAR."
To said such action by the mainland police deprived the man of rights set out in the Basic Law and called on the central government to intervene.
As reported by The Standard earlier, the Shenzhen Public Security Bureau briefed police and port control officials recently on stepping up patrols and deploying more officers at border points with Hong Kong.
Authorities fear Hong Kong protests could lead to mainlanders holding demonstrations.
Mainlanders have already voiced support for Hong Kong protests by posting mainland ID cards and passports with accompanying slogans.
Some also wrote in simplified Chinese that they were touched by Hongkongers' determination and backed them in their fight for justice.
Yang Guang, a spokesman for the Hong Kong and Macau Affairs Office, said on Monday that anti-government protests should not be allowed to spread from the SAR to the mainland.