I caught my coworker red-handed talking shit about me in a common room and confronted her about it. She is the type of person who I suspected would gossip or be in a work clique and this confirms it. I walked in and she went silent although I had already heard her shittalking from the hallway. I told her if she wanted to say something to me say it to my face and now i realize the person she is. I emailed my boss and HR about the situation. Any advice on what to tell HR when I inevitably get called into their office after the weekend?