Last year, five booksellers of Causeway Bay Bookstore in Hong Kong mysteriously disappeared. After months of detention in mainland China, four of them were returned to Hong Kong, but the fifth still remains in Chinese custody.

According to The New York Times, PEN America has, in response to the abductions, released a new seventy-page report, which details and critiques China’s increasingly authoritative actions toward book publishers. According to the report, the publishers are increasingly going out of business due to widespread fear that Hong Kong’s autonomy has been compromised by mainland China’s interference. (The “one country, two systems” principle has governed Hong Kong’s relationship to the mainland since 1997, when a treaty returned control of the island from the United Kingdom to China.)

“The constellation of theories, none mutually exclusive and none confirmed, has created an atmosphere of uncertainty,” the report reads. “It is impossible for independent publishers who produce books critical of China’s rulers to know how not to cross the line and become the next targets because it is unclear where that line is drawn. The only sure response is to take no steps at all.”

The report also outlines the difficulty Hong Kong–based publishers are having with finding printers for China-focused books. As an example, Bao Pu, who runs New Century Press, was told by his printer that it “would not print any more of his books, regardless of content.”

Image Credit: PEN America.