How long does an investigation usually take? July 28, 2021 21:43 This varies depending upon the complexity of the case and how cooperative the parties are. We usually complete an investigation within six months, although it could be much shorter or longer than this. Related articles Who has the burden of proving discrimination? What if I am discharged? What is the legal definition of sexual harassment? Are breaks or lunch periods required? How do I get a copy of my commission complaint file?