Hong Kong bookseller Lee Bo, whose disappearance three months ago led to speculation that he had been abducted by mainland security agents, has returned to the city.

He crossed into Hong Kong from Shenzhen yesterday afternoon using his Hong Kong identity card, said police. He later requested that the missing person report filed by his wife be cancelled.

His reappearance draws a line under the episode. But it will take more to quell jitters that China overstepped its legal jurisdiction.

Mr Lee, 65, and four associates, who also vanished last year, ran a publishing firm and bookshop in Causeway Bay specialising in salacious gossip about China's leaders.

When Mr Lee, the only one to disappear from Hong Kong, went missing on Dec 30, his wife reported that his travel documents were still at home, triggering talk that he had somehow been smuggled out.

Many believed all five men had been taken away because they were preparing to publish a book about President Xi Jinping's personal life.

The episode undermined confidence here in the "one country, two systems" framework, which spells out Hong Kong's legal autonomy. Under its Basic Law, no overseas law enforcement agencies can operate in Hong Kong.

Yesterday, the police said Mr Lee told them that he had not been abducted and that he had made his way voluntarily to the mainland "with the help of friends". The Immigration Department will investigate further before deciding whether to take action against him for leaving Hong Kong illegally.

In an interview with a Chinese television station earlier this month, Mr Lee said he had gone to the mainland to help with investigations into his colleagues. One of them, Mr Gui Minhai, confessed to returning to China to turn himself in for a fatal drink driving accident 13 years ago. The rest confessed to "unauthorised" sales of books to mainlanders.

The men's disappearances were among a broader crackdown on dozens of human rights lawyers, labour activists and ethnic minority figures in China, where Beijing appears to be tightening its control.

Last week, Beijing-based journalist Jia Jia was about to board a flight en route to Hong Kong, when the police escorted him away for his "involvement in a case", his lawyer told the South China Morning Post. Mr Jia was linked to a petition calling for Mr Xi to resign.

Asked about the case during a regular press briefing on Monday, a Foreign Ministry spokesman said in Beijing: "Lots of things happen in China every day. There are lots of things worth reporting in China, and you should not focus so much on individual cases."