HONG KONG (REUTERS) - Chinese police have confirmed for the first time that three of five Hong Kong booksellers who went missing were being investigated for "illegal activities" in China, according to a letter sent to Hong Kong's police on Thursday.
The disappearances have prompted fears that mainland Chinese authorities may be using shadowy tactics that erode the "one country, two systems" formula under which Hong Kong has been governed since its return to China from British rule in 1997.
The three men; Lui Por, Cheung Chi-ping and Lam Wing-kee who were linked to the Causeway Bay Books store, had had "criminal compulsory measures" imposed on them, Chinese police in the southern province of Guangdong bordering Hong Kong told Hong Kong police in a letter on Thursday.
This was the first indication by mainland Chinese authorities as to the fate of this trio since they were reported missing last November, without giving any other detail of their location or condition other than that they are in China.
Hong Kong police referred to the letter from the Chinese police in a statement but did not make it public in full.
Two other Hong Kong booksellers who also disappeared, Gui Minhai and Lee Bo, are believed to have been abducted or coerced from Thailand and Hong Kong respectively, and taken to China, according to foreign diplomats familiar with the case.
The Hong Kong police said China had also given them a handwritten letter from Lee Bo, stating that he was in China. In the letter, Lee declined a request by Hong Kong police to meet with him. He gave no further details.
The Hong Kong police, however, said they still wanted to meet Lee "as soon as possible" and were pressing Beijing for more information on the other three.
No specifics were given on the alleged crimes of Lui, Cheung and Lam, other than that they were "suspected to be involved" in a case related to Gui, a Swedish passport-holder, who made a tearful confession on Chinese television last month for a fatal hit-and-run incident over a decade ago.
Gui, and Lee - a dual British and Chinese national - had been owners of the same publisher and bookstore that specialised in gossipy books critical of China's Communist Party leaders.
The British government is still waiting for responses to its diplomatic requests for information and access to Lee.
Authorities including in the European Union and the United States have expressed concerns over the disappearances.
So far, Chinese authorities have not made any substantial statements explaining Beijing's role in the disappearances, nor how the men ended up in China.
China's Foreign Ministry has said Hong Kong is China's domestic affair and "no foreign country has the right to interfere" in this matter.
Britain handed Hong Kong back to China under agreements that its broad freedoms, way of life and vaunted legal system would remain unchanged for 50 years.