Normally, the company’s regulations with regards to mentoring and supervision are designed to prevent the personal involvement of the supervisors and avoid their bias against the new workers. If these rules were indeed in place, the HR department, as well as the management, are responsible for handling instances of employee misconduct. An investigation should be performed by the HR staff using re-tests and interviews to determine if there was indeed a bias against the supervisee.
If the supervisor was biased, she should be punished according to the company’s procedure for cases of moderate misconduct. The timeline for the investigation should not exceed three to four weeks, and the punishment should be executed within a week of investigation results.