> At what other point in history has police distributed a completly illegal tool onto unsuspected and non-targeted civilians?

It might be a stretch but..

"LSD was one of the materials tested in the MKUltra program. The final phase of LSD testing involved surreptitious administration to unwitting non-volunteer subjects in normal life settings by undercover officers of the Bureau of Narcotics acting for the CIA." - http://en.wikipedia.org/wiki/Project_MKUltra