Advice on this friendship?

Ahh the classical Good Me... Bad Friend mix up. I was involved with a relationship like this once with my friend Chris L and he started doing bad things like stealing and smoking and other bad stuff. Im a boy and so is he and i have a high temper so personally i fought him in a fight and won but obviously that was the wrong way to go. What i would do is say to your friend " Hey lets not be bff's anymore, lets just talk occasionally" and walk away. You can still be her friend just not the best friends you were, thats the best way to go.