Do I have a case of defamation?

A co worker accused me of harassment the investigation took two weeks I was not found guilty and was told I can return to work, that weekend the coworker published to a third party my name stating I had harressed them and that they wanted others to reach out to them if they were treated the same by me. I emailed the copies to my HR manager letting them know my name was now being slandered by this individual to the whole company, they stated the investigation was over and closed my name was cleared and I can sell legal council outside of my workplace. I was planning on starting the search for the lawyer the same week I was to return to work. I was called that same week from the HR manager stating there was now another accusation against me. I am extremely frustrated because I now feel she has gotten her friends to make up more false accusations. I am wanting to know if a lawyer is now needed