[Mamzelle]

Following them home has proven to be useful.

In the early days of terrorism, it was the water supply that interested and frightened me most, rather than antrhax and smallpox. You can make a lot of poison easily on a petri dish and terrify a lot of people (though not kill many) if you can just get that poison into a significant water source. Say, on Sunday night in prep for Monday morning coffee.

[FourPeas]

A biologist/college professor friend of my dad said the same thing twenty years ago. With a bit of rudimentary knowledge and access to a water plant much harm can be done.