A cache of weapons and a fake bomb manufacturing operation were uncovered by police at a densely populated public housing estate in Cheung Sha Wan yesterday. A 31-year-old man was arrested after officers from Kowloon West Regional Intelligence Unit raided a flat in Wo Ping House at Lei Cheng Uk Estate at about 3.30pm. Police said besides seizing a cache of weapons, including one stun gun, four air pistols and a beef knife, equipment for making 'imitation bombs' were also found. But police stressed that the 'bombs' had no killing power because they did not contain explosives. A police spokeswoman said the officers found wires, batteries, plastic tape, one bullet shell, one test tube containing some brown-coloured powder, and three small plastic bags with a similar powder. She said an examination confirmed the powder was not explosive. 'We are still trying to establish what this powder contains, but it is certainly not explosives.' Yesterday's was the second such discovery by police in nine days. On August 14 police seized a semi-automatic pistol, 15 knives and an extendable baton from a Mongkok shop believed to have been used by the 14K triad as a weapons depot.