Hi Synaps3,
Sorry to hear about this! We can't predict what will happen I'm afraid and so it's hard to know what advice to give you - it depends on exactly what was on there and what your professor is like, but I think it would be extremely unlikely that he would go to the police with it! If it is just some articles then you are fine, there is nothing wrong with reading articles about drugs. If it is forum posts, he'd likely have a hard time proving they are definitely yours..
This isn't really the sort of question we cover in here I'm afraid (check the BDD guidelines in my sig) and I can't think of any other forum on BL that would cover it either so I'm going to have to close it - but good luck, I really hope things turn out okay!