When foreigners (waiguoren - 外国人) work in China like I did for twenty years, they are guests of the Chinese government.  It is important not to proselytize one's religion in China, although hundreds of missionaries from the United States, Canada and other countries do so.  They've been able to convert many Chinese to Christianity.  They've been able to do so by learning how to be circumspect.  Sometimes they develop 'guanxi -(relationships)' with important people.  No doubt the PSB (Public Security Bureau) had its eye on these people from the get go.  Had they obeyed the law against proselytizing there would never have been this problem When I arrived in China in the early 1990s, I knew a lot about China; it's history and culture.  When I left twenty years later, I knew less about China than when I first arrived. Any Sinologist recognizes that. So how can people who comment here know more about China than I do.