[Centurion2000]

It would be possible for the government to have a highly potent poison even in small amounts such as botox stored within and upon the release of a certain coded transmission to trigger it release if they wanted to just kill someone. Yes that would be possible

A small piece of ricin will do you in just as well as a bullet.

[weikel]

Ricin would work too I vaguely remember the Russians( this was on some cold war history channel type thing) sent a Bulgarian intelligence agent to kill a defector with an umbrella that was tipped with Ricin. Its nearly chemically untraceable too.