CLEAN : Hong Kong activists demand the release of missing booksellers

The transcript covers a press conference addressing the disappearance of Mr. Libor in Hong Kong. It suggests that his disappearance is linked to the publication of politically sensitive books critical of the Chinese Communist regime. The speaker accuses the public security agents of violating Hong Kong's basic law and the one country, two systems policy. A call is made for the immediate release of the Causeway Bay bookshop owners, who are believed to be unlawfully detained.

What does the text imply about the relationship between the basic law and the one country two systems policy?

What actions does the speaker call upon the Chinese Government to take?