HONG KONG • A bookseller who went missing in mainland China and re-emerged under detention has returned to Hong Kong and asked police to drop their investigation into his initial disappearance.

Mr Lam Wing Kee is one of five Hong Kong-based booksellers who published salacious titles critical of Beijing and disappeared at the end of last year, a case which fuelled growing fears that Beijing was tightening its grip on the semi-autonomous Chinese city.

It later emerged that all of them had been detained in China, where four - including Mr Lam - are under official investigation over the import of banned books from Hong Kong to the mainland.

Mr Lam is the latest to return to Hong Kong - three of the other booksellers have also made short trips but have quickly gone back over the border.

Hong Kong police said they met Mr Lam yesterday. Like the others who had returned, he requested the cancellation of his "missing person" case and said he did not need official help, police said.

Critics have said the retractions were made under pressure from Beijing. Hong Kong police have said they are continuing to investigate the booksellers' cases.

Mr Lam was one of three who went missing from southern mainland China in October. Another, Swedish citizen Gui Minhai, went missing from Thailand, and the fifth, Mr Lee Bo, from Hong Kong.

Mr Lee's disappearance led to accusations that mainland law enforcement agents were operating illegally in the city.

Mr Lam's colleagues Cheung Chi Ping and Lui Por returned to Hong Kong in March on bail, but are reported to have quickly gone back to the mainland. Mr Lam is also on bail. Mr Lee resurfaced in the city the same month, only to go back across the border less than 24 hours later. He insists he is a free man and is just assisting the mainland authorities.

AGENCE FRANCE-PRESSE