This story, in particular is tragic. The summary: college hippie sells pot and ecstasy to friends. Gets busted. The cops offer a deal: be an informant, and we'll go easy on you. Girl falls for it. They wire her up and send her to buy way more drugs than ever before, a gun, and other such out-of-character behaviors.
A few days later, the police find her body.
Reason's blog often runs stories about the "isolated incidents" wherein "drug warrior" thugs break into homes with "no knock warrants", harass, abuse, and sometimes kill the residents, then realize that it was the wrong house. Sadly, Reason can't be arsed to tag their entries, so I can't link to the library of "isolated" incidents that they've collected.