Tens of thousands of protesters have attended an annual pro-democracy march in Hong Kong.
Protesters held photos of Lam Wing Kee, one of five booksellers who went missing last year after publishing books critical of China's leaders.
Mr Lam returned to Hong Kong in June, saying he had been detained in the mainland for eight months.
He was due to lead Friday's march but dropped out, reportedly over fears for his personal safety.
The case of the booksellers raised international concerns that Hong Kong's judicial independence and freedom of speech were being eroded.
Albert Ho, a lawmaker who has been advising 61-year-old Mr Lam, told the BBC: "He feels he is under intense surveillance."
"He has been physically followed by unknown people. He is under intense pressure."
Mr Ho added that arrangements were being made for Mr Lam to go to a safe house.
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http://www.bbc.co.uk/news/world-asia-china-36680898
