HONG KONG >> A Hong Kong bookseller whose disappearance sparked international concern said Sunday that he was so despondent during his detention by authorities in mainland China that he considered suicide.

Lam Wing-kee told The Associated Press that he thought about using his clothes to hang himself but couldn’t find a way to do it in the small room where he was kept under constant watch for five months.

Lam and four other men who worked for a Hong Kong publishing company disappeared last year, only to turn up months later in police custody on the mainland.

The publisher specialized in gossipy books on China’s communist leadership that were popular with Chinese visitors to Hong Kong but banned on the mainland.

Their case raised concerns that Beijing is tightening its hold on the former British colony and undermining its considerable autonomy. Hong Kong retains rule of law and civil liberties such as freedom of speech unseen on the mainland under its status as a special Chinese administrative region that runs until 2047.

Lam returned to Hong Kong on Tuesday, following three other colleagues who had done so earlier. But he went off the script written for him by the Chinese authorities and spoke out Thursday at a news conference, giving a harrowing account of his ordeal, which unfolded when he paid a visit to the neighboring mainland city of Shenzhen in October.

He was handcuffed and blindfolded, taken on a 13-hour train ride and then confined to a small room for months while he was interrogated about the authors writing for the Mighty Current publishing company and the customers at its Causeway Bay Bookshop.

Lam said his interrogators were particularly interested in details about the writers behind two of the company’s books.

One was about a Communist Party directive that urged officials to curb the spread of ideas such as press freedom, judicial independence, civil rights, civil society and the party’s historic mistakes. It was based on a high-level internal circular leaked in 2013 that was seen as an attempt to attack Western democratic ideals and crush dissent to protect the party’s rule.

The other book was about the love lives of President Xi Jinping and other Chinese leaders. Lam said he gave them only what limited information he had about the books’ authors.