What if Eric was a hitman as well (...one that acts dumb but realllllly..isn't)? Like he's been keeping tabs on Michael's work at the university because of his access to clubs and such. Sort of like what Ashley is doing.

Maybe even have those plaster fossils hollow in the center and filled with drugs or diamonds or etc etc . He's using the guise of friendship as a means to have Michael store it at his place so he doesn't get caught with them. 

It's up to you~ I just thought of building it all up until the day where Michael realizes that nearly everyone around him is lying-- and he doesn't know who to trust. Etc Etc.