The "sonic device" was a highly lethal weapon employed by the Hands of Blue. It was small enough to be carried in a coat pocket and when activated caused massive internal bleeding from every orifice and opening (including under fingernails and sweat pores) in the human body. When activated, the weapon emitted an increasingly high pitched tone, and as the tone grew more intense, the injuries sustained by nearby targets became more and more severe. The weapon functioned with a broad area of effect and spared only those who were immune to its effects (those employing the weapon) and those who were too far away. Its use appeared to be to remove all inconvenient potential witnesses. Anyone within several feet of the user would die from the effects of the device, making it difficult for others to harm the user.