Not too long ago I wrote about the horribly racist (and largely unproductive) "stop and frisk" program of the NYPD. Well, hold on to your monocle, lest the gasp you are about to let forth sends it tumbling to the floor to shatter or humorously plop into your morning Earl Grey and splash your fine garments: it turns out that is not the end of the problems plaguing New York's finest.
A retired narcotics detective from the NYPD recently testified under oath that the planting of drugs on suspects to get an arrest is a pretty regular practice of the NYPD narcotics officers.
Of course, this problem isn't confined to New York; if you take a moment to dig around, you'll find a similar story from pretty much any city of size. And the reason this happens everywhere is not because police are especially corrupt or amoral, but because of the nature of the drug war itself -- people want to see people busted for drugs (or at least the people that matter, like mayors and legislators), police are basically operating with no direct supervision and no meaningful restrictions on their actions, and there's a bunch of poor black and brown people that won't cause any meaningful uproar even when they're imprisoned for no reason.
In fact, if you really understand the role of the drug war (and mass incarceration in general), you'll see that it's far less about any form of crime control or deterrence (mainly because we've been locking up large numbers of people for drug crimes for at least 30+ years now and they've been conclusively proven do neither of those things). Instead, it's about finding a way to control all those pesky black and brown people who insist on continuing to exist. Since we can't enslave them or legally exclude them from our day-to-day lives anymore, we need somewhere for them to go so we don't have to deal with them (here's a fancy-pants academic explaining it in detail).
But hey, at least we can rest comfortably knowing that few, if any, police officers will ever be punished for repeatedly sending innocent people to exorbitant prison sentences. And that's a pretty comforting thought...