A FRIGHTENING, multi-bladed knife destined for Melbourne's streets was among a cache of weapons seized by Customs yesterday. Officers detected the 50cm knife during an X-ray of air cargo from the US at Sydney airport last month. Bound for Melbourne, the four-pronged attack knife was found with a small arsenal including a sword stick, trench knives, a double-edged dagger and other knives. The four-bladed knife has a silver-studded cuff wrapping around the wrist while the hand grasps the handle. The handle is connected to two small flick-knife sized blades and two 25cm larger knives, with a total length of 50cm....