Simon Cheng, a staff member of Britain’s consulate in Hong Kong, who has been detained by Chinese authorities in the neighboring mainland city of Shenzhen, is seen in an unknown location in this undated photo obtained from the Facebook page “Free Simon Cheng.”

Simon Cheng, a staff member of Britain’s consulate in Hong Kong, who has been detained by Chinese authorities in the neighboring mainland city of Shenzhen, is seen in an unknown location in this undated photo obtained from the Facebook page “Free Simon Cheng.”