Workplace Rumors. What to do?

Myself and another tech are hearing rumors about us in the workplace. We’ve heard them from more than one relaible source. People say our manager is telling them that he/she came up to them and told us (the techs) certain things BUT he/she never told us (the techs) these things. For example he/she told someone that he/she told us that “I am the manager and what ever I says goes, no exceptions. And that you two have real attitude problems and it going to stop NOW!” When in fact she never said such things to us. What are we to do. It’s making for a real uncomfortable work enviroment. We’ve talked to his/her boss and HR but nothing is being done. Do you think we have an case against him/her? Thoughts suggestions??