4,000 people marched through Hong Kong accusing China of unlawful detention and abduction.
Lam Wing-kee was among five booksellers who mysteriously disappeared in 2015.
Around 6,000 officers have been deployed ahead of Zhang Dejiang's visit to Hong Kong.
It's finger(nail) lickin' good
Editor at Ming Pao newspaper sacked after running front-page report on Panama Papers.
Trio reportedly lured the university lecturer in a flat before killing him over a financial dispute.
The most financially secretive states according to Tax Justice Network's Financial Secrecy Index 2015.
Longest-reigning emperor Kangxi's seal set the third highest price for a Chinese seal sold at auction.
Passenger violated strict rules against bringing in fruit undeclared.
Chinese state media has criticised the film and that has aroused new concern about mainland influence.
Scotland also achieved their first win in 21 attempts at a major global tournament.
Hong Kong take on Scotland in a Group B qualifier on 12 March.
The Saltires are still yet to win a match at the ICC World Twenty20 competition in six attempts.
Afghanistan take on Hong Kong in Group B qualifier at Nagpur on 10 March.
Afghan batsmen Mohammad Shahzad and Asghar Stanikzai combine for a 14-run victory in Nagpur, Maharashtra.
News of probe comes as Hong Kong plays a T20 World Cup qualifier match.
Zimbabwe face Hong Kong in the 2016 T20 World Cup Qualifiers on Tuesday. Find out how to follow the match live in the UK.
Companies like Nap Lounge are charging professionals up to an hour of shut-eye for just over 92p.
Search engine's design shows lanterns going into the sky to mark the coming of spring.
The riot took place after officials tried to remove illegal hawkers who had set up their shops in Mong Kok.
London remains 'ideally positioned to be the home base' for HSBC, the lender has said.
White roses are supposed to symbolise pure and innocent love.