HONG KONG, January 3 (Reuters): Hong Kong opposition lawmakers protested on Sunday outside Beijing’s representative office in the Chinese-ruled city over the disappearance of a bookseller who specialises in publications critical of the Communist Party government. Lee Bo, 65, a major shareholder of Causeway Bay Books, “vanished” on Wednesday after he went to fetch books from his warehouse in the city, Lee’s wife told Hong Kong media. She said her husband had called her from a mainland Chinese number to tell her he was safe but would not reveal his location, the South China Morning Post (SCMP) reported on Sunday. She said Lee spoke to her in Mandarin even though the pair usually communicated in Cantonese. Lee is the fifth person linked to the bookstore to have gone missing in the past two months. Others include Gui Minhai, owner of Mighty Current, the publishing house that owns the bookstore, the SCMP reported. Missing person reports were filed for three others, it said. The disappearances have stoked fears of mainland Chinese authorities using shadowy tactics that erode the one country, two systems formula under which Hong Kong has been governed since its return to Chinese rule from Britain in 1997. The city’s constitution guarantees wide-ranging personal freedoms and independent law enforcement.