Undercover agents can be really tough to pick out.
A couple 'connections of connections' got busted by an undercover who was really deep into the lifestyle. He was pierced and tattooed and smoked herb with the guys and was even sleeping with one of the dealers' girlfriends. It got pretty ugly- fistfights and whatnot- and no one suspected for a moment that he was a narc until he showed up at their araignments.
Grow your own.