Mystery of 5 missing men alarms Hong Kong residents

A deepening mystery in Hong Kong sounds like the plot of a political thriller, but it's all too real. Five people have vanished since October, and all of them are connected to a publishing company and book store that specializes in books critical of Communist China's leaders.

Since Hong Kong was handed over from British to Chinese rule back in 1997, it has retained some autonomy, reports CBS News correspondent Seth Doane. Notably, it has its own legal system and freedom of speech and press. With the case of these missing booksellers, some worry those freedoms may be under threat.

Sandwiched between a pharmacy and a nail salon and up a cramped stairwell is Causeway Bay Books, which was closed Friday. In the hallway, there are some of the gossipy, salacious titles known for criticizing China's leaders. One book talks about China's first lady Madame Peng Liyuan's private life. Another title predicts the downfall of China's President, Xi Jinping.

But now the story of this bookstore itself is harder to believe since five men tied to it have disappeared.

The most recent, Lee Bo, was expected home for dinner December 30 but never showed.

Days later, a faxed letter purportedly from Lee said: "Due to some urgent matters...I have made my...own way to the mainland... It might take a bit of time."

Protesters, carrying photos of the missing booksellers, have demanded answers. There was no record of Lee crossing the Hong Kong border.

"Why is the case of the missing bookseller so important?" Doane asked Hong Kong legislator Albert Ho.

"Well, I think it concerns the basic security and safety of Hong Kong people," Ho said.

Ho worries Chinese authorities -- or their agents -- may have illegally taken Lee into the mainland.

"We are concerned about a case of political kidnap," Ho said.

"You are calling this a political kidnapping?" Doane asked.

"Must be. The circumstantial evidence have driven us to an irresistible conclusion," Ho said.

China's government-linked Global Times newspaper wrote Lee was "not taken away by Chinese mainland police officers," but was critical of the bookstore, calling it a source of "political rumors" and "evil influence."

Amnesty International's William Nee notes China doesn't have jurisdiction to come to Hong Kong and detain someone.

"In China right now, this type of thing is completely normal... The government regularly detains and sometimes puts its critics in secret detention," Nee said. "Hong Kong has a different system and that's why people are so alarmed in this case."

The concern here is that mainland China is reaching more and more into Hong Kong's affairs. CBS News contacted China's central government, its police, as well as border officials and local authorities but haven't received any explanation or answers as to where Lee Bo may be.