When an employee complains of discrimination, emphasize to that employee that the claim and all related details will be kept confidential and that information will be disclosed to others only on a need-to-know basis. Assure the employee (complainant) that the employer has a zero-tolerance policy for retaliation.
Select a neutral, objective and properly-trained investigator to gather and review evidence, conduct interviews and obtain the necessary facts from the complainant, the alleged wrongdoer(s) and all witnesses. Every stage of the investigation, including all interviews, should be carefully documented.
Ensure that the person(s) investigating the discrimination claim has access to all the information, (e.g., personnel files) as well as to the employees who may have information relevant to the investigation.