how to get my roomates heroin-addict friend out of my apartment

[2point0T]

Ok so my one roomate has a friend who is on parole, pissed hot for weed, his po didnt do anything, he started doing heroin, he sells weed pills everything, and he is on parole. A very stupid kid obviously, but here is the problem, he stays at my apartment all the time because my roomate (who he has been friends with since they were very little) lets him stay there. He is always nodding out, another friend of ours found a bunch of H bags in our bathroom trash can, and they found needles in his bag, the works, he def shoots up in our bathroom. I have never liked the kid, I don't want someone potentially overdosing in my bathroom because on top of the trouble that woud come with it, I myself am under court supervision, and I have been doign very good but I dont want this kid here. I have caught him eating my food multiple times, selling drugs in the apartment, selling/buying in the hallway right outside of my apt, and he sleeps there and makes a mess and never cleans up (even tho these are not as serious as the shooting up in the bathroom is). So my roomates have confronted him, other friends have told his parents, nothing seems to be happening. My one roomate is afraid when he leaves he will jsut start doing it even more, I personally don't care what the kid does, as long as it isnt in my apartment

So how do I get rid of this kid? I am sure there are numerous options, I don't want to get in trouble at all, and I don't want to seem like a dick to my roomate, I would like to do this in the most fair way, even though he is not fair by obeying my wish that he never comes back. If i call the cops when he was there, would it matter that my other roomate says its ok hes there? I just really need help, this is a touchy situation. This kid should be in jail for a long time with the kinda **** hes been doing, and thats where I would like to see him. So legally what are my options.

Sorry for the length.