How do I get rid of a crackhouse?

A drug dealer lives in the apartment complex one of my friends lives in. At all hours day and night, people are in and out. If a car pulls up, sometimes the guy goes out to see what they need, goes back inside, then comes out with their stuff. Sometimes they go in and stay for a bit. They come in on foot, bikes, cars, whatever, some stay until the next day and stagger out so wacked out of their gourds it's amazing they can still walk. When the door opens, it smells like a Snoop Dog afterparty from the weed smoke pouring out, but I highly doubt that's all they are selling. Yesterday morning they must have finally crashed too hard to open the door, because people were banging on the door pleading to be let in. A guy stopped by that afternoon so twitchy he looked like he had tourettes, with track marks covering his arms. Last night TWENTY THREE cars pulled in, loaded up, and took off. I guess they needed to stock up for a party maybe.

My friend is afraid to turn them in to the police because she is afraid they will mess up her car or break into her apartment if she does. The apartment manager doesn't care as long as the rent is paid. Is there a way to report the crackhouse completely anonymously?