HONG KONG -- Three men have been arrested for suspected manslaughter in a fire that broke out in Wang Fuk Court, a residential area in Tai Po of Hong Kong, on Wednesday afternoon, the Hong Kong Police Force said at a press briefing on Thursday.

The fire had left 55 people dead by Thursday afternoon, the police said.

Police investigation suggested that the protective nets, waterproof canvas and plastic cloth covering the buildings might fall short of fireproof standards. The police also found that polyurethane foam was used to seal windows of elevator lobbies in an unaffected building in the residential area, and pointed to the flammable material as a possible cause for the rapid spread of fire.

The three men were executives of a construction company responsible for installing these materials for the renovation of the buildings. The suspects aged between 52 and 68 include two company directors and a project consultant whose gross negligence was believed to have caused heavy casualties.