False Accusations in the Workplace

My question involves defamation in the state of: New Jersey

I have been working at a healthcare facility for over a year now in a supervisory position. The previous supervisor didn't have much control over the department and the employees. I have extensive experience in this role from a previous employer. I have experienced friction from 1 employee who, previous to my employment, wasn't a highly regarded employee. This employee has recently approached HR with fabricated stories involving harassment against me. HR was able to definitively refute 1 of the stories, however they couldn't find any witness to confirm or deny the others. Since the other stories could not be confirmed, HR informed me that no action could be taken against her since it was he said/she said. Since the complaint this employee admitted to a another employee that she tried to get me fired. The other employee approached HR with this information. Since there was no other witness to this, HR again took no action. HR was also made aware of a text message this employee sent to another employee, where she wished that I died in a car accident. HR again did nothing. Thanks for listening, and any advice would be appreciated.

Thanks,
Michael

False Accusations in the Workplace