Someone on my course I think has a personality disorder and spent time in jail-how should I handle them?

This person I got to know back in 2006/2007 and he told me about a criminal past which involved prison in his youth. I am the only person that knows this on the course. I found them very charismatic and charming but also very competitive during this time and quite self-obsessed. I shared a house with this person from 2007 until a few months ago and their sellf-obsession, competitiveness became increasingly prominent and increasing arrogance. I believe this person is narcissistic and we kind of had a run-in which I tried to resolve by straight talking. I found this person was fine to my face but gradually it became obvious they were "splitting" within the house and among course mates this involves spreading quite nasty stories about me. Because of the way this has been done its quite difficult to pin down and confront as it is all indirect. Although I am not saying I don't have my faults I believe this person has quite major personality flaws including his past and the way that he influences people through his charisma. Is this typical of a personality type and if so how should I handle things better? I think things are going to be a bit icy for the final year of the course. I have kind of lost friends though this as he seems to have influenced people in a way that makes them loyal to him. I can categorically say that I have not tried to do the same to him.