I just discovered that my "know it all" co-worker is a liar and a fraud! He has forged university degree to get the current job which is a systems' analyst at a Telecommunications company. I discovered this because one of his former university colleagues asked me if worked together? And I told him what we do, then he asked me how it was possible for him to get that job without a degree.
I found out that he never completed his degree from a whole lot more people, and its possible that he forged his degree when he used to tutor at that same university. I asked him whether he completed his degree and with full eye contact he said yes.
Our work relationship has now deteriorated and we can't really communicate anymore. I guess he is playing mind games with me. How can I deal with this situation? Should I talk to my manager about it? And how should I convey the message?