Think about it, cobalt is too slow. Polonium is ideal - you need a much smaller amount, and in five years it's gone, ten years, it's undetectable. Except that it decays into a specific isotope of lead, which could raise some questions, but you call it a toxin, and hope that the evidence gets destroyed in the process...
Think about it, cobalt is too slow. Polonium is ideal - you need a much smaller amount, and in five years it's gone, ten years, it's undetectable. Except that it decays into a specific isotope of lead, which could raise some questions, but you call it a toxin, and hope that the evidence gets destroyed in the process...