Police have arrested five men, aged 36 to 43, over the murder of a 40-year-old watchman at a waste recycling centre in Hang Tau, Sheung Shui, last night.

The watchman was found inside a container office and some iron and copper waste worth $30,000 was missing. His hands and legs were bound by electric wires and his head was wrapped in a t-shirt.

Officers raided two units in Kowloon and eight scrap yards in the New Territories North early today, arresting the five and seizing iron and copper waste from one location.