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

In an interview Sunday, 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 publishing company disappeared last year, only to turn up months later in police custody on the mainland.

The publisher specialized in books on China's communist leadership that are banned on the mainland.

Their case raised concern Beijing is tightening its hold on the former British colony and undermining its considerable autonomy.